How to migrate from Microsoft 365 to Google Workspace
Use Google's data import tool in the Admin console to move Exchange Online mailboxes, OneDrive and SharePoint Online into Gmail, Calendar and Drive, then switch MX.
How do you migrate from Microsoft 365 to Google Workspace?
This copies email, calendars, contacts, OneDrive files and SharePoint sites from Microsoft 365 into Google Workspace. Google's Data import tool, built into the Google Admin console, does the copying and leaves Microsoft 365 untouched. You run a first import, then a delta import (a top-up of only what is new or changed) just before and after you change the MX record (the DNS setting that tells the internet where to deliver your email).
- Recommended route: Google Data import (built into the Google Admin console)
- Order: Build the people, groups and shared drives in Google first, because Data import only copies into accounts and drives that already exist.
- 6 phases: Get ready, Set up Google Workspace, Import email, Import files and sites, Switch over and Check and close.
- You're done when: Every user and site report shows zero failed items, or only failures you have explained.
The time depends on how much mail and how many files you have, because each import runs in the background until it finishes.
Built into the Google Admin console, and copies mail, calendars, contacts, tasks, OneDrive and SharePoint. Google says Google Workspace Migrate, its older self-hosted tool, is no longer available for Exchange Online, SharePoint and OneDrive sources from the end of 2026.
Other options and when to use them
- Data import, advanced method: You have 1,001 users or more, or need Outlook rules, In-Place Archive mailboxes, calendar permissions or event attachments imported. It runs on your own API quota through an app you register in Microsoft Entra ID.
- Google Workspace Migration for Microsoft Outlook (GWMMO): A few users have mail kept in Outlook PST files on their PCs, which Data import cannot read.
- Third-party platform such as CloudM or BitTitan MigrationWiz: You need content Data import leaves behind, or want vendor support.
Build the people, groups and shared drives in Google first, because Data import only copies into accounts and drives that already exist. Then copy in the background while people keep working in Microsoft 365, switch the MX record, run the last top-up, and remove Microsoft 365 last.
- Inventory, cut-off date and Data import method (default or advanced)The method decides how many users fit in one import and whether rules and archive mailboxes come at all, so choose it before you build anything.
- Google domain, users with licences, Google Groups and room resourcesData import does not create accounts. Shared mailboxes need a group to land in, and room calendars need a resource to map to.
- A shared drive for each SharePoint siteThe SharePoint site list needs each shared drive ID and a Google user with Manager access to it.
- Pilot: a few users and one SharePoint site, then lock the mappingChanging a mapping after an import does not work with a delta, and Google warns about re-importing SharePoint data within 14 days, so get the mapping right on a small group.
- Main imports for mail, OneDrive and SharePointThey are copies, so people keep working in Microsoft 365 while they run.
- Delta import, MX change, then one more deltaThe first delta catches most changes. Google says an MX change can take up to 72 hours to be recognised, so the second delta picks up mail that still reached Exchange Online.
- Rebuilds: SharePoint pages, lists, flows and PlannerData import copies files, not these. Keep Microsoft 365 read-only until each one is rebuilt and tested.
- Export reports, exit imports, then remove Microsoft 365 licencesExiting an import deletes its reports, and removing licences starts deleting the mailboxes and files, so these come last.
Built-in and third-party tools treat these differently. Tick each one off once you have decided.
Download this checklist (Excel)How each tool handles it
Built-in methodData import, default method: runs on Google's shared API quota (the cap on how fast tools can call Google's services), for up to 1,000 Exchange Online users or 500 OneDrive users per import. It does not import In-Place Archive mailboxes, Microsoft 365 Group mailboxes, Outlook rules, event attachments or calendar permissions. The advanced method uses your own quota through an app you register in Microsoft Entra ID, runs batches of up to 5,000 users, and includes all of these.Tip: If you need any advanced-only item, plan the advanced method from the start rather than switching later.
Google Workspace Admin Help: What's imported from Exchange OnlineHow each tool handles it
Built-in methodData import: copies mail from the start date you set. Folders become Gmail labels; a folder path over 225 characters loses its label but the messages still import. Deleted and junk mail are left out unless you tick them. Messages over 150 MB, categories, flags, pinned and scheduled status, and the Notes folder are not imported.Tip: Agree a cut-off date with the business, and warn users that flags and categories will be lost.
Google Workspace Admin Help: What's imported from Exchange OnlineHow each tool handles it
Built-in methodData import: rules import only with the advanced method, and only when "Import message rules as filters" is turned on. Many rule types do not convert, including rules using categories, flags, forwarding, redirects or dates.Tip: Ask users to note their important rules before cutover, so they can rebuild the ones that do not convert.
Google Workspace Admin Help: What's imported from Exchange OnlineHow each tool handles it
Built-in methodData import: In-Place Archive mailboxes import with the advanced method only. It reads Exchange Online, not PST files stored on PCs or file shares.Google Workspace Migration for Microsoft Outlook (GWMMO)Lets users import their own email, calendar and contacts from an Outlook account or PST file. The Google account must exist first, and Google advises running only one GWMMO instance per user.Tip: List who still has PST files during the inventory, and schedule them one user at a time.
Google Workspace Admin Help: What's imported from Exchange OnlineHow each tool handles it
Built-in methodData import: a shared mailbox mapped to a Google Group imports as a collaborative inbox, but read and unread status does not carry over. Microsoft 365 Group mailboxes import with the advanced method only, capped at 100 posts per thread. The Global Address List (the shared company address book) and contact lists do not move.Google Cloud / G Suite Connector by MicrosoftMicrosoft Entra provisioning creates users, groups and group memberships in Google Workspace, about every 40 minutes. Microsoft does not list which group types are supported, so test a distribution list in the pilot.Tip: Create the groups and their members before you map any shared mailbox.
Google Workspace Admin Help: What's imported from Exchange OnlineHow each tool handles it
Built-in methodData import: copies primary and additional calendars from the start date. Room calendars come only with a CSV mapping to a Google resource. Teams meeting links stay as Teams links, not Google Meet. Calendar permissions and event attachments need the advanced method. Events a user edits in Google Calendar are not re-imported by later deltas.Tip: Ask organisers to add Google Meet to recurring meetings after cutover, and to edit meetings only in Google from then on.
Google Workspace Admin Help: What's imported from Exchange OnlineHow each tool handles it
Built-in methodData import from OneDrive: imports up to 180 versions of each file, newest first, and files keep their Office format. For SharePoint sites, how many versions come: not stated in Google's documentation: test it in your pilot.CloudM MigrateNot stated in CloudM's documentation: test it in your pilot.BitTitan MigrationWizNot stated in BitTitan's documentation: test it in your pilot.Tip: Check pooled Google storage against current OneDrive and SharePoint use before the main import.
Google Workspace Admin Help: What's imported from OneDriveHow each tool handles it
Built-in methodData import from OneDrive: items shared with external users stay shared with them, and they get email notices when items are shared. Google allows one shareable link per item, so where several links exist the most restrictive applies. Files created or last modified by an external user are not imported. SharePoint: files, folders and permissions are copied, and site groups map to Google Groups you create first.Tip: Tell regular partners before the import that they may receive sharing emails from Google.
Google Workspace Admin Help: What's imported from OneDriveHow each tool handles it
Built-in methodData import: Personal Vault files, favourites, folder shortcuts and colours, file expiry dates, SharePoint pages, lists and Power Automate flows, and Planner tasks are not imported. To Do tasks lose recurrence and due times.Tip: Keep Microsoft 365 read-only until each rebuild is tested by its owner.
Google Workspace Admin Help: What's imported from OneDriveHow each tool handles it
Built-in methodData import from OneDrive and SharePoint: you can import only files created or modified after a date, exclude file types, and exclude files above a size. Folders always import.Tip: Agree filters with owners in writing, because filtered files stay only in Microsoft 365.
Google Workspace Admin Help: Default data import method for OneDriveHow each tool handles it
Built-in methodData import: a delta run after you change a user's target address does not copy data to the new address, and importing the same data again creates duplicates. For SharePoint, Google warns that within 14 days of a completed import, a new import of the same data, or to a second place, can move it out of the first place.Tip: If a mapping must change, exit the import and create a new one for those users or sites only.
Google Workspace Admin Help: Import from SharePoint OnlineHow each tool handles it
Built-in methodData import: a delta import copies new or changed items and retries failed ones. Run it after the main import, again after the MX change, and keep running it until mail stops reaching Exchange Online.Tip: Google says an MX change can take up to 72 hours to be recognised, so plan at least one delta after that.
Google Workspace Admin Help: Default data import method for Exchange OnlineHow each tool handles it
Built-in methodData import: "Exit and delete import" removes the configuration and its reports for good.Tip: Export the user, summary and site reports to your project folder before you exit any import.
Google Workspace Admin Help: Default data import method for Exchange Online
- 1
Get ready
Before you startWatch out: Data import reads Exchange Online mailboxes, not PST files (Outlook data files) kept on PCs or file shares.
Ways around it
- List who still has PST files, and import them separately, one user at a time.
Tools that can do it
- Google Workspace Migration for Microsoft Outlook (GWMMO)Lets users import their own email, calendar and contacts from an Outlook account or PST file. Accounts must exist first.
Show the detailed steps (4) →Watch out: Data import, default method: each import takes up to 1,000 mail users or 500 OneDrive users, and Outlook rules and In-Place Archive mailboxes import only with the advanced method.
Ways around it
- Plan the advanced method and its own API quota from the start if you need more.
- 2
Set up Google Workspace
Watch out: Data import does not create accounts or groups, so the Global Address List (the shared company address book) and distribution lists become manual work.
Ways around it
- Create Google Groups and their members by hand before you import.
Tools that can do it
- Google Cloud / G Suite Connector by MicrosoftCreates users, groups and group memberships in Google Workspace from Entra ID, about every 40 minutes. Test a distribution list in the pilot.
Check your DNS records before and after the change
Show the detailed steps (4) → - 3
Import email
Watch out: Data import: messages over 150 MB, Outlook categories and flags, the Notes folder and the Global Address List do not move.
Ways around it
- Save attachments over 150 MB by hand, and warn users that flags and categories are lost.
Show the detailed steps (5) →Watch out: Data import: a delta run after you change a user's target address does not copy data to the new address, and importing the same data again creates duplicates.
Ways around it
- If a mapping must change, exit the completed import and create a new one for those users only.
- 4
Import files and sites
Watch out: Data import: Personal Vault files, shortcuts, files owned by external users, SharePoint pages, lists and flows do not import.
Ways around it
- Rebuild pages, lists and flows in Google Sites, AppSheet or Apps Script, and keep Microsoft 365 read-only until they are done.
Watch out: Data import from OneDrive: Office files stay as Office files, and up to 180 versions of each file come across. Both use Google storage.
Ways around it
- Check pooled Google storage against OneDrive use, and filter old or very large files.
Show the detailed steps (4) →Watch out: Data import from SharePoint: Google warns that within 14 days of a completed import, importing the same data again, or to a second place, can move it out of the first place.
Ways around it
- Get the site mapping right in the pilot, then run only delta imports for 14 days.
- 5
Switch over
After the main imports finishWatch out: Google warns that leftover Microsoft 365 MX records can stop mail working, and that an MX change can take up to 72 hours to be recognised.
Ways around it
- Remove every old MX record, and keep running delta imports until mail stops reaching Exchange Online.
Turn this phase into dated tasks with the cutover planner
Show the detailed steps (4) → - 6
Check and close
After the final deltaShow the detailed steps (2) →Watch out: Data import does not copy data back to Microsoft 365, and removing Microsoft 365 licences starts deleting mailboxes and files.
Ways around it
- Keep Microsoft 365 licences until every check passes and the rebuilds are finished.
- Every user and site report shows zero failed items, or only failures you have explained.
- The only MX record is smtp.google.com, Gmail is active, and SPF and DKIM pass.
- Every user sends, receives and opens files in Google on every device.
- No new mail or file edits reach Microsoft 365 since the final delta.
Tools named in this plan are independent third-party products, not endorsed by the platform vendor and not paid placements. Check the tool's own documentation and run a pilot first.
What does each step involve?
Open a part when you reach it in the plan. Each step says where to go, what to do and what you should see.
About this migrationWhat it covers, limits at a glance
Google now steers Microsoft 365 migrations to Data import, a self-guided tool built into the Admin console. It copies Exchange Online mail, calendars, contacts and To Do tasks, OneDrive files and permissions, SharePoint Online sites into shared drives, and Teams chat messages. It copies, it does not move: nothing is deleted in Microsoft 365.
Google's migration product matrix says Google Workspace Migrate will no longer be available for Exchange Online, SharePoint Online and OneDrive from the end of 2026, so new projects should plan on Data import. On-premises Exchange, SharePoint Server and file shares still use other Google tools.
1What you need before step one
| Need | Details | Where to get it |
|---|---|---|
| Google Workspace admin | A super administrator, who runs every Data import. | Google Admin console (https://admin.google.com) > Account > Admin roles |
| Microsoft 365 admin | A Global Administrator, who signs in when Data import connects to Exchange Online, OneDrive and SharePoint Online. | Microsoft 365 admin center (https://admin.microsoft.com) > Roles > Role assignments |
| Google Workspace licences | A Google Workspace edition that covers the features people use, and a licence with Gmail turned on for every target user. | Google Admin console > Billing > Subscriptions; check current pricing |
| Domain verified in Google | Needs the Domain settings administrator privilege and sign-in to your DNS host. | Add a domain to Google Workspace |
| Users created first | Data import does not create accounts, so every user exists and is licensed before you import. | https://knowledge.workspace.google.com/admin/users/add-or-update-multiple-users-from-a-csv-file |
| Data import | The import tool in the Admin console. Default method up to 1,000 Exchange users and 500 OneDrive users; larger moves use the advanced method. | Use the Google Workspace data import tool |
| Shared drives | Created before you build the SharePoint site CSV, because the CSV needs each shared drive ID. | Google Drive (https://drive.google.com) > Shared drives > New; IDs from Admin console > Drive and Docs > Manage shared drives |
| DNS access | Sign-in to your DNS host for the MX change, SPF and DKIM at cutover. | Change MX records, set up SPF, set up DKIM |
| Files to prepare | User mapping CSV (Source Exchange Email, Target GUser), OneDrive user and identity CSVs, a SharePoint site CSV, each under 10 MB, plus Google Groups and calendar resources for lists and rooms. | Mailbox and data inventory, with counts from Microsoft 365 admin center > Users > Active users |
| Browser | Pop-ups allowed from Microsoft sites in the browser you use for the Google Admin console, for the Microsoft 365 sign-in. | Your browser settings |
2Pick the right method and size the job4 steps
- 1
Count users per workload
Where: Your Mailbox and data inventory, with user counts from Microsoft 365 admin center (admin.microsoft.com) > Users > Active usersCount the Exchange Online, OneDrive and SharePoint users you will import. Google splits the data import tool into a default method for organisations of 1 to 1,000 users and an advanced method for 1,001 users or more. The default method uses Google's shared API quota. The advanced method uses your own quota and runs in batches.
You should see: The inventory states which method each workload will use. - 2
Check the edition
Where: Google Admin console (admin.google.com) > Menu > Billing > SubscriptionsGoogle lists Business Starter, Standard and Plus, Enterprise Standard and Plus, Education, Frontline, Essentials and Nonprofit editions as supported for the data import tool. Confirm your edition here and against Google's announcement before you buy.
You should see: Your subscription is one of the supported editions. - 3
List what each user needs in Google
Where: Your Identity and licence mapping sheetMap each Microsoft 365 plan to a Google Workspace edition by the features people use: storage, Vault retention, device management, Meet recording, and security controls. Check Google's current edition comparison and pricing pages.
You should see: Every user group has a chosen Google Workspace edition. - 4
Note sources the data import tool does not cover
Where: Your Mailbox and data inventory, checked against Google's migration product matrixExchange Server, SharePoint Server, file shares and Box use Google Workspace Migrate or Google Workspace Migration for Microsoft Exchange (GWMME), as shown in Google's product matrix. PST files use GWMMO or GWMME; see install GWMMO.
You should see: Any source outside Exchange Online, OneDrive and SharePoint Online has a named tool in the plan.
3Prepare Google Workspace and Microsoft 3654 steps
- 1
Verify the domain and create users
Where: Google Admin console > Menu > Account > Domains > Manage domains, then Menu > Directory > UsersVerify your domain in Google Workspace (add a domain to Google Workspace). The data import tool does not create accounts, so create every user first and assign a licence (bulk create users in Google Workspace). Turn on Gmail, Calendar and Drive for the users you are importing to under Menu > Apps > Google Workspace.
You should see: The domain shows as verified, every target user exists with a licence, and the three services show ON for them. - 2
Create shared drives for SharePoint sites
Where: Google Drive (drive.google.com) > Shared drives > New, then Google Admin console > Menu > Apps > Google Workspace > Drive and Docs > Manage shared drivesEach SharePoint Online site is imported into a shared drive. Create the shared drives before you build the CSV, because the CSV needs each shared drive's ID. Add a Google user with Manager access to each drive. Google says to find shared drive IDs on the Manage shared drives page in the Admin console.
You should see: Each planned shared drive appears in Manage shared drives with a manager, and you have recorded its ID. - 3
Have a Global Administrator ready
Where: The browser you will use for the Google Admin console (pop-up settings)The Google super admin connects to Microsoft 365 by signing in as a Global Administrator. Allow pop-ups from Microsoft sites in that browser.
You should see: The Global Administrator credentials are to hand and the browser does not block the Microsoft sign-in window. - 4
Tell users the import is a copy
Where: Email from your User communication packChanges they make in Outlook or OneDrive after the import will only come across in a delta import. Give them the dates of the first import, the delta and the cutover.
You should see: Users have the dates before the first import starts.
4Import Exchange Online mail, calendars and contacts5 steps
| Item | Imported? | Notes from Google's documentation |
|---|---|---|
| Mail folders | Yes, as labels | Folder paths longer than 225 characters do not become labels, but the messages still import |
| Messages over 150 MB | No | Attachments also skip if Gmail blocks the file type |
| Categories, flags, Notes folder | No | Pinned, flagged and scheduled status are lost |
| Outlook rules | Advanced method only | Imported as filters when "Import message rules as filters" is set; forwarding and redirect rules are not supported |
| In-Place Archive | Advanced method only | For active users |
| Calendar events | Yes | From the start date; Teams meeting links stay as Teams links; event colours do not move |
| Contacts | Yes | Global Address List and contact lists do not move |
| To Do tasks | Yes | Recurrence and due times are lost; Planner tasks do not move |
- 1
Connect
Where: Google Admin console (admin.google.com) > Menu > Data > Data import & export > Data import, signed in as a super administratorFor Exchange Online click Import, then Connect, and sign in to Microsoft 365 as a Global Administrator. See also use the Google Workspace data import tool.
You should see: The Exchange Online import page shows the connection, and Data import appears as an authorised API client under domain-wide delegation. - 2
Map users
Where: Data import > Exchange Online > user mapping sectionFor 20 users or fewer the tool suggests matches you can edit; review them and click Save Changes. For more than 20, upload a CSV with the headers
Source Exchange EmailandTarget GUserusing Upload CSV. If a user's UPN and mail values differ, Google says to use the UPN.Source Exchange Email,Target GUser will@contoso.com,will@contoso.com maria@contoso.com,maria@contoso.comYou should see: The Tasks list shows the CSV upload succeeded, or the suggested mappings are saved. - 3
Choose settings
Where: Data import > Exchange Online > Edit settingsSelect data types (Emails, Calendar events, Contacts, To Do Tasks) and a start date. Deleted and junk email are excluded unless you tick Include deleted email and Include spam email. You can exclude folders by name (comma-separated,
Travel/Asiafor subfolders) and tick Copy additional calendars. Room calendars can only be mapped with a CSV. Click Save changes.You should see: The settings summary on the import page shows your choices. - 4
Start, monitor and export reports
Where: Data import > Exchange Online import pageClick Start import and watch the counters for discovered, imported, skipped, failed and warning items. You can leave the page without stopping it. Click Export user report or View data import logs before you exit, because exiting deletes the configuration and reports.
You should see: The counters rise, and you receive an email with statistics and attached reports when the import finishes. - 5
Run a delta import before cutover
Where: Data import > Exchange Online import page > delta import optionA delta import copies new or changed items and retries failures. Do not run a delta if you changed the Target GUser column after the first import. Exit and create a new import instead.
You should see: The counters update with the new items and the completion email arrives again.
5Import OneDrive into My Drive4 steps
- 1
Connect to OneDrive
Where: Google Admin console > Menu > Data > Data import & export > Data importFor Microsoft OneDrive click Import, then Connect to Microsoft OneDrive, and sign in as a Global Administrator.
You should see: The OneDrive import page opens with the upload options for the user list and identity map. - 2
Upload the user list and identity map
Where: Data import > Microsoft OneDrive > Upload CSV (twice), then the Tasks listThe user list has one column,
Source OneDrive User. The identity map hasSource EmailandDestination Email. Each CSV must be smaller than 10 MB. Click Upload CSV, select the file and click Open for each. The default method handles up to 500 OneDrive users per import.Source OneDrive User will@contoso.com Source Email,Destination Email will@contoso.com,will@contoso.comYou should see: Tasks shows both uploads as successful. If one fails, delete it and upload again. - 3
Set filters
Where: Data import > Microsoft OneDrive > Edit settingsYou can tick Only include files created or modified after the following date, Exclude specific file formats and Exclude files larger than the following size, then click Save. Folders always import.
You should see: The settings summary shows your filters. - 4
Start and review
Where: Data import > Microsoft OneDrive import pageClick Start import. Files keep their format, so Word, Excel and PowerPoint files stay as Office files in Drive. Up to 180 versions per file are imported. OneNote notebooks arrive as folders. Use Export summary report to review failures.
You should see: Counters for files discovered, imported, skipped and failed rise, and a completion email arrives with reports.
7Teams chats and the things that need rebuilding3 steps
- 1
Decide on Teams chat history
Where: Your Mailbox and data inventory; the import itself runs from Google Admin console > Menu > Data > Data import & export > Data importGoogle lists Microsoft Teams chat messages as a data import tool source, with default and advanced methods. Decide which chats and channels are worth importing into Google Chat and which can stay archived in Microsoft 365.
You should see: The inventory records a keep, import or archive decision for each team. - 2
Plan shared mailboxes
Where: Google Admin console > Menu > Directory > Groups, then the Exchange Online import CSVShared or user mailboxes mapped to a Google group import as a collaborative inbox. Read and unread status does not carry over to groups. Create the groups first, then map each shared mailbox to its group in the
Target GUsercolumn.You should see: Each shared mailbox has a Google group and a row in the mapping CSV. - 3
Recreate distribution lists and rooms
Where: Google Admin console > Menu > Directory > Groups, and Menu > Directory > Buildings and resources > Overview > Resource managementCreate Google Groups for distribution lists and calendar resources for rooms (create the building first), then map rooms in the calendar CSV.
You should see: Each distribution list and room has a Google equivalent and room calendars import into their resources.
8Switch MX to Google4 steps
- 1
Run final delta imports
Where: Google Admin console > Data > Data import & export > Data import > each open importRun a delta for mail and files just before the change so the gap is small. Lower the MX TTL a day ahead (lower DNS TTL).
You should see: Each delta completes and its completion email arrives. - 2
Change the MX record
Where: Your DNS host's control panel > contoso.com > DNS records, then Google Admin console > Menu > Account > Domains > Manage domains > Activate GmailGoogle's current MX value is
smtp.google.comwith priority 1. Remove the old Microsoft 365 MX record, because Google warns that leftover MX records can stop mail working. Then click Activate Gmail for the domain. Changes can take up to 72 hours to be recognised. See change MX records.contoso.com. MX 1 smtp.google.com.You should see: nslookup -type=mx contoso.com returns only smtp.google.com, and a test message from outside arrives in Gmail. - 3
Run one more delta after propagation
Where: Google Admin console > Data > Data import & export > Data import > Exchange Online importMail that reached Exchange Online during propagation comes across in a final delta import.
You should see: The final delta shows the late messages as imported. - 4
Update SPF and DKIM
Where: Your DNS host's control panel, and Google Admin console > Menu > Apps > Google Workspace > Gmail > Authenticate emailAdd Google to SPF (set up SPF) and turn on DKIM signing in Google Workspace (set up DKIM). Remove Microsoft 365 from SPF when it no longer sends for the domain.
You should see: The SPF record includes Google and Authenticate email shows DKIM as authenticating.
9Exit imports and decommission2 steps
- 1
Export logs, then exit
Where: Google Admin console > Data > Data import & export > Data import > each completed importExport logs and user reports, then click Exit import and Exit and delete import. This removes Data import from domain-wide delegation. You cannot start a new import of the same type until you exit a completed one.
You should see: The import no longer appears as open, and its client is gone from Security > Access and data control > API controls > Manage Domain Wide Delegation. - 2
Keep Microsoft 365 read-only for a period
Where: Microsoft 365 admin center > Billing > Licenses, and your Decommission checklistKeep licences long enough to answer "where did this go" questions and meet your retention obligations, then remove them.
You should see: The decommission checklist records the retention end date and the date licences were removed.
What can go wrong, and how do you avoid it?
The detail behind the plan: options compared, and what experienced engineers check first. Tap any item.
Compare all the ways to do this4 options
Data import, default method
Low effortBest for: Up to 1,000 Exchange Online users and 500 OneDrive users per import
- Built into the Google Admin console and runs on Google's shared API quota
- Data import covers mail, calendars, contacts, To Do tasks, OneDrive, SharePoint sites and Teams chat
- Copies only: nothing is deleted in Microsoft 365
- Does not import PST files or Outlook rules
- Some content stays behind, such as OneDrive Personal Vault files
Data import, advanced method
High effortBest for: Organisations of 1,001 users or more
- Uses your own API quota and runs in batches, up to 5,000 Exchange Online users per batch
- Can import Outlook message rules as Gmail filters, which the default method does not
- More set-up, because you supply and manage the API quota
- Batches need more planning and monitoring
GWMMO for PST files
Medium effortBest for: A small number of users with mail in Outlook PST files
- Google lists it in its product matrix for small numbers of users
- Users can run it themselves
- Windows and Outlook only, one user at a time
- Covers PST and Outlook data only, not OneDrive or SharePoint
Third-party migration platform
Medium effortBest for: Projects that need features the data import tool lacks, or vendor support
- Options such as CloudM and BitTitan MigrationWiz cover Microsoft 365 to Google Workspace
- One vendor across mail and files
- Extra product to buy: check the vendor's current pricing
- Check each vendor's supported data types first
Plan on Data import: Google's product matrix says Google Workspace Migrate is no longer available for Exchange Online, SharePoint Online and OneDrive from the end of 2026. Use the default method up to 1,000 users and the advanced method above that. Add GWMMO only for PST files, and compare third-party platforms only if you need content Data import leaves behind.
Plan on the data import tool, not Google Workspace MigrateReduces risk
Google's product matrix says Google Workspace Migrate for Exchange Online, SharePoint Online and OneDrive is no longer available from the end of 2026.
Build the project around Data import (Admin console > Data > Data import & export). Use other Google tools only for sources it does not cover, such as on-premises Exchange or PST files.
Data import reads Exchange Online mailboxes, not PST files kept on PCs or file shares. Google's own desktop tool imports that PST content into Gmail, Calendar and Contacts.
- Google Workspace Migration for Microsoft Outlook (GWMMO)Lets users import their own email, calendar and contact data from an Outlook account or PST file. Admins can push it as an MSI, Google advises running only one GWMMO instance for each user, and accounts must exist first.
Pick the default or advanced method by size and featuresSaves time
The default method runs on Google's shared API quota and caps imports at 1,000 Exchange users or 500 OneDrive users. Rules and In-Place Archives import only with the advanced method.
If you need Outlook rules as filters, archives, or more than the default limits, plan the advanced method and its own API quota from the start.
Use the start date and filters to cut volumeSaves time
Every year of mail and every old file adds import time. Deleted and junk mail are excluded by default.
Agree a retention cut-off with the business, set the start date for mail and the created or modified date filter for files, and exclude file types or sizes nobody needs. Keep older data in Microsoft 365 for the read-only period instead.
Expect Office files and version history to use Drive storageCost lever
OneDrive files keep their Office format and up to 180 versions per file are imported, so storage use in Drive can be higher than users expect.
Check pooled storage in your Google edition against OneDrive usage before the import, and use the size and date filters for very large or old content.
Never change the mapping and then run a deltaReduces risk
A delta after a Target GUser or Destination Email change does not copy data to the new address, and a second import of the same data creates duplicates.
Lock the identity mapping after the pilot. If a mapping must change, exit the completed import and create a new one for the affected users only.
Respect the 14-day caution on SharePoint importsReduces risk
Google warns that within 14 days of a completed SharePoint import, creating a new import for the same data or importing it to a second location can move data from the first location to the second.
Get the site-to-shared-drive mapping right in the pilot, then leave completed sites alone for 14 days apart from delta imports.
Export reports before you exit any importCompliance
Exit and delete import removes the configuration and reports for good, and you need them to prove what moved.
Export the user or site report and logs to Google Sheets from Tasks, store them with your data validation report, then exit.
Plan for what the import leaves behindUser impact
SharePoint pages, lists and flows, Planner tasks, the Global Address List, Outlook categories and flags, Personal Vault files and files owned by external users do not import.
List these per team with an owner and a target (Google Sites, AppSheet, Apps Script, Google Groups) before cutover, and keep Microsoft 365 read-only until they are rebuilt.
The import does not rebuild the directory, so the Global Address List and distribution lists otherwise become manual work in Google Groups. Microsoft's provisioning connector creates users, groups and group memberships in Google Workspace from Entra ID and keeps them in step. SharePoint pages, lists, flows, Planner tasks and Outlook categories and flags still need the rebuild plan above.
- Google Cloud / G Suite Connector by MicrosoftMicrosoft Entra provisioning creates users and provisions groups and group memberships in Google Workspace, with changes applied on the next sync cycle (about every 40 minutes). Only assigned or in-scope groups are created and Microsoft does not list which group types are supported, so test a distribution list in the pilot.
Warn users about Teams links in imported meetingsUser impact
Imported calendar events keep their Teams meeting links, which stop being useful once Microsoft 365 is retired.
Ask organisers to edit recurring meetings in Google Calendar to add Meet after cutover, starting with the meetings that run past your Microsoft 365 end date.
Remove the old MX records completelyReduces risk
Google warns that leftover MX records can stop mail working, and changes can take up to 72 hours to be recognised.
Lower TTL a day ahead, replace every Microsoft 365 MX record with smtp.google.com priority 1, and run a final delta after propagation to catch mail that landed in Exchange Online.
How do you check it worked, or roll back?
Full validation checklist8 checks
Run these before you declare the migration complete. Record the results in the data validation report.
| Check | How to check | What good looks like |
|---|---|---|
| Every Exchange Online user imported | In the Google Admin console open Menu > Data > Data import & export > Data import > Exchange Online, read the imported, skipped, failed and warning counters, and select Export user report before you exit. Compare with your Mailbox and data inventory. | Every mapped user is present, failed items are zero or explained, and the final delta ran after MX propagation. |
| Mail, calendars, contacts and tasks arrived | Sign in to Gmail, Google Calendar and Google Contacts as a sample of users and compare folders, recent mail, future meetings and contacts with Outlook on the web. | Outlook folders appear as labels, future meetings and contacts are present, and missing items match the skipped items in the report. |
| OneDrive files reconcile | In Data import > Microsoft OneDrive select Export summary report, then open My Drive for a sample of users and compare folder trees and file counts with their OneDrive. | Files and folders match, apart from the known exclusions such as Personal Vault, shortcuts and files owned by external users. |
| SharePoint sites landed in the right shared drives with the right access | Open each target shared drive from Google Drive > Shared drives, compare content with the SharePoint site, and check members in Google Admin console > Apps > Google Workspace > Drive and Docs > Manage shared drives. | Each site in the CSV has its files in the right shared drive, and site members map to the expected Google users or groups. |
| Shared mailboxes, groups and rooms work | Send a test from outside to each group that replaced a shared mailbox or distribution list, and book each calendar resource from Google Calendar. | Collaborative inboxes receive mail, distribution groups deliver, and rooms accept bookings. |
| MX, SPF and DKIM point at Google | Run | The only MX record is smtp.google.com, Gmail is active for the domain, and SPF and DKIM pass. |
| Users work in Google on every device | Ask each user to confirm they use Gmail and Google Drive on desktop and phone, and that Outlook and the OneDrive app are no longer used for work. | Every user sends, receives and opens files in Google without help. |
| Microsoft 365 is no longer receiving mail or edits | In the Exchange admin center run Mail flow > Message trace for recent inbound mail, and sort a sample of OneDrive and SharePoint libraries by Modified. | No new mail is delivered to Exchange Online and no files have changed since the final delta. |
Rollback planIf it goes wrong
Roll back if
- The Exchange Online import shows many failed users or items that cannot be fixed before cutover
- Mail stops arriving after the MX change and cannot be fixed in the agreed window
- SharePoint content or permissions are badly wrong in the shared drives
- Users cannot sign in to Google Workspace on cutover day
Point of no return
The data import tool copies data and leaves Microsoft 365 unchanged; stopping an import does not remove what was already copied. You can switch back while the Microsoft 365 mailboxes, OneDrive and SharePoint sites still exist. The point of no return is removing Microsoft 365 licences or deleting users and sites, because that starts the removal of their mailboxes and files. Google's tool does not copy data back to Microsoft 365, so mail and files created in Google after cutover must be moved separately.
- 1
Put MX back to Microsoft 365
Where: Microsoft 365 admin center > Settings > Domains > contoso.com > DNS records (for the value), then your DNS host's control panelAdd the Microsoft 365 MX record shown in the admin center, or the value in your DNS cutover record sheet, and remove the smtp.google.com record. Keep Microsoft 365 in SPF.
nslookup -type=mx contoso.com 8.8.8.8You should see: Public resolvers return the Microsoft 365 MX record and the admin center shows the domain as healthy. - 2
Stop running imports
Where: Google Admin console > Menu > Data > Data import & export > Data import > each open importSelect Stop import on any running import and export the reports. Data already copied stays in Google.
You should see: No import is running. - 3
Send users back to Outlook and OneDrive
Where: Your User communication pack, and each user's devicesTell users to work in Outlook, OneDrive and Teams again until the retry, and not to edit the copies in Google.
You should see: Users confirm they are back in Microsoft 365. - 4
Move back work done in Google
Where: Gmail and Google Drive in a browser, then Outlook on the web and OneDriveFor mail received in Gmail after the MX change, users forward the important messages to their Microsoft 365 mailbox. For files created or changed in Google, download them and upload to OneDrive or the SharePoint site. For many users, plan a reverse move using the Google Workspace to Microsoft 365 guide.
You should see: Microsoft 365 holds the latest mail and files from the cutover window. - 5
Keep Microsoft 365 licences in place
Where: Microsoft 365 admin center > Billing > LicensesDo not remove licences or delete users until a retry has succeeded and your decommission checklist is signed off.
You should see: Every user still has a licensed mailbox and OneDrive.
Agree the triggers and who decides before the go / no-go meeting. Use the rollback plan template.
Common problems and fixes7 errors
Imported email count is lower than the count in Exchange OnlineCause: Some items are not supported: messages over 150 MB, drafts without a From header, items in Notes, and deleted or junk email if not selected.
Fix: Compare against Google's list of what is imported, and run a delta import to retry failed items.
Delta import does not copy data to the new addressCause: The Target GUser or Destination Email was changed after the first import.
Fix: Exit the completed import and create a new import with the corrected mapping.
Cannot start a new importCause: A completed import of the same type is still open.
Fix: Export its reports, then select Exit import and Exit and delete import.
Duplicate secondary calendars after a second importCause: The same data was imported again with Copy additional calendars selected.
Fix: Clear Copy additional calendars when you re-import the same data.
CSV upload fails or stays pendingCause: The file is malformed or larger than 10 MB, or the upload stalled.
Fix: Delete the file, create a new CSV with the exact headers, and upload again. Check the Tasks list for the result.
Some mail folders are missing as labelsCause: The folder path is longer than 225 characters.
Fix: Messages still import. Shorten folder names in Outlook and run a delta import, or apply labels after import.
Duplicate files in Drive after re-running OneDrive importCause: A second import was created for the same data set.
Fix: Use a delta import on the existing import for changes. Only start a new import when the mapping changes.
Frequently asked questions
Is Google Workspace Migrate still an option for Microsoft 365?
Google's product matrix says Google Workspace Migrate for Exchange Online, SharePoint Online and OneDrive is no longer available from the end of 2026. Use Data import instead.
Does Data import convert Office files to Google Docs?
No. OneDrive files are imported in their existing format. Users can open Office files in Drive or convert them later.
Does Data import delete anything in Microsoft 365?
No. It copies data. Exchange Online, OneDrive and SharePoint content is left in place.
How many users can I import at once?
The default method handles up to 1,000 Exchange Online users or 500 OneDrive users per import. The advanced method handles up to 5,000 users per batch for Exchange Online.
Are Outlook rules migrated?
Only with the advanced method and the "Import message rules as filters" setting. Rules that are disabled, in error, or forward and redirect mail are not imported.
Can I migrate PST files?
Not with Data import. Google's product matrix lists GWMMO for small numbers of users and GWMME for PST imports.
Official sources
13 official pages this guide is based on
Vendors change limits and features, so confirm details on the source before you rely on them. Last checked 4 Nov 2026.