AboutFree templates
How-to · Google Workspace

Migrate email with the Google Workspace data import tool

At the end your users' email (and, from Exchange Online, calendars and contacts) is copied into their Google Workspace accounts, with a report of anything that failed.

Updated 11 steps7 official sources
Start hereBack to the playbook
Before you start

What you need before step 1

Applies to: Google Workspace; sources documented by Google: IMAP providers, Microsoft Exchange Online, another Google Workspace account, and a personal Gmail account. Google's help page addresses still use the name new data migration service; the pages themselves now call it the data import tool.

Admin roles you need

  • Google Workspace super administrator (Google says you must be signed in as a super administrator; resellers cannot run IMAP imports for customers)
  • Exchange Online source only: a Microsoft 365 Global Administrator to authorise the connection
  • Google Workspace source only: a super administrator of the source account to approve the request

Licences

  • Each target user exists in Google Workspace with a licence and Gmail turned on

Also have ready

  • IMAP source: the IMAP server name, and each user's address and password or app password (see Find IMAP settings for your current email provider)
  • IMAP source: IMAP turned on for the source accounts and for the target users. For your own users, follow Google's article Turn POP & IMAP on or off for users.
  • IMAP source: Google says the server must accept connections from Google's outbound IP ranges, and use port 993 with IMAP over SSL. Servers without a trusted TLS certificate need Google Workspace Migration for Microsoft Exchange (GWMME) instead.
  • Google says you cannot start a new import until you exit a completed one
Step by step

11 steps

  1. 1

    Open Data import

    Where: Google Admin console (admin.google.com) > Menu > Data > Data import & export > Data import

    Sign in as a super administrator and follow the menu path, or go straight to https://admin.google.com/ac/migrate?journey=206. Older guides may describe a Data migration page; this is the location Google documents now.

    You should see: A page listing import sources, each with an Import button: Exchange Online, IMAP, Google Workspace emails and Gmail.
  2. 2

    Connect an IMAP source

    Where: Data import > IMAP > Import

    Skip if your source is not IMAP. Select Import under IMAP. In IMAP server address, pick your provider from the list or type the host name (for example imap.example.com). Select Test connection.

    You should see: A Connected notification.
  3. 3

    Or connect Exchange Online

    Where: Data import > Exchange Online > Import > Connect

    Select Import for Exchange Online, then Connect, and sign in to Microsoft 365 as a Global Administrator. Allow pop-ups from Microsoft sites if the sign-in window is blocked.

    You should see: The connection is authorised, and Data Import appears as an authorised API client on the Domain-wide delegation page.
  4. 4

    Or connect another Google Workspace account

    Where: Data import > Google Workspace emails > Import

    Enter the Source super admin email address and select Request authorization. The source super admin opens the emailed link, signs in and selects Authorize. Then select Verify authorization in your account. The request expires after 24 hours.

    You should see: Status changes to Connected.
  5. 5

    Map source users to Google users

    Where: Data import > your source > Select users

    20 users or fewer: enter each mapping on screen (for IMAP: IMAP email address, IMAP password, Workspace email address, then Add user) and select Save changes. For Exchange Online the tool suggests mappings for you to review.

    More than 20 users: select Upload CSV with a file whose header row matches the source, as below. Open Tasks to confirm the upload succeeded. Limits per import: IMAP 100 users and under 128 MB; Exchange Online 1,000 users and under 10 MB; Google Workspace 1,000 source users and under 128 MB. One source user cannot map to several Google users, but several sources can map to one.

    Source ImapUser,Source ImapPassword,TargetGUser
user1@example.com,password1,user1@contoso.com

Source Exchange Email,Target GUser
user1@contoso.com,user1@contoso.com

Source GUser,Target GUser
user1@oldcompany.com,user1@contoso.com
    You should see: The mapping table lists every user, or Tasks shows the CSV upload completed.
  6. 6

    Choose import settings

    Where: Data import > your source > Import settings

    Set the Start date (mail from that date up to the day you start is imported). Optionally tick Import deleted emails, Import spam emails or Exclude specific folders. For exclusions, enter folder names separated by commas and list subfolders by full path, for example Travel,Travel/Asia. For Exchange Online you also choose data sources: Email, Calendar events, Contacts, Tasks. Select Save.

    You should see: The settings are saved and Start import is available.
  7. 7

    Start the import

    Where: Data import > your source

    Select Start import. Google says this also grants domain-wide delegation and creates a client ID for Data Import in your account. You can leave the page; the import keeps running.

    You should see: Status changes to In progress.
  8. 8

    Monitor progress

    Where: Admin console > Data > Data import & export > Data import

    Watch the counters, which update in real time: Discovered items, Warning, Failed, Skipped, Successful, Users processed, and Emails discovered, imported, skipped and failed (plus calendar and contact counters for Exchange Online). When the import finishes, you receive an email with statistics and the reports attached.

    You should see: Users processed reaches the number of mapped users and Failed stays low.
  9. 9

    Download the reports

    Where: Data import > View data import logs or Export user report > Tasks

    Select View data import logs or Export user report. If Tasks does not open, select the Tasks icon, then under Your Tasks open the file. Reports open in Google Sheets, or download as CSV if too large. The user report shows each source and target user with Status (Running, Failed or Completed) and email counts; the data import report lists each item with Success, Warning, Error or Skipped and an error code and description.

    You should see: A Google Sheet listing users and any failed items.
  10. 10

    Run a delta import at cutover

    Where: Data import > your source > Delta import

    After you change MX records, run a delta import to copy mail that arrived at the old system since the first pass, and to retry failed items.

    You should see: The delta import completes and the counters show only new items.
  11. 11

    Exit the completed import

    Where: Data import > your source > Exit import

    Export any reports you want to keep first. Select Exit import, then Exit and delete import. Google says this deletes the Data Import client ID and removes it from domain-wide delegation, and you can no longer see the import's settings or reports.

    You should see: The source returns to its starting state with an Import button, ready for another import.
From experience

Expert tips

Run a pilot batch first

Import two or three mailboxes, including one large one, and read both reports before the main run. It shows connection, password and folder problems while they are cheap to fix.

Plan batches around the per-import limit

One import holds up to 100 users for IMAP and 1,000 for Exchange Online or another Google Workspace account. Split large organisations into waves by department so each wave can be checked and cut over separately.

Use delta imports for cutover and retries

Run the main import days ahead, change MX, then run a delta import to copy anything added since. Google says a delta import also retries data that failed in the initial import, so try it before troubleshooting individual messages.

Read the two reports together

Start with the user report and look for a Failed status or a non-zero Emails failed count. Then filter the data import report for Error (not imported) and Warning (imported but incomplete) and use the source identifier to find the message or label.

Ask users to close other mail apps (IMAP)

Google notes the IMAP server may hit its connection limit and the import cannot connect. Ask users to close desktop and phone mail apps on the old account during the import.

Stopping does not roll back

Google says stopping an import can take a few minutes and does not remove anything already imported. Check the date range and user mapping before you start, because a wrong mapping means cleaning up data by hand.

Check it worked

How to confirm it worked

  • The user report shows Status Completed for every user.

  • Sign in as a test user at https://mail.google.com and check that folders appear as labels with the expected message counts.

  • Exchange Online: check the test user's Calendar and Contacts for imported items.

Undo

How to reverse it

Rollback:

An import cannot be rolled back. Google says stopping an Exchange Online import does not delete content already imported. To remove imported mail you would delete it from each user's mailbox. The source mailboxes are not changed by the import.

Troubleshooting

Errors you might see

Entry already exists

Cause: The CSV map repeats a source address.

Fix: Remove duplicate source addresses and upload the map again. The same target user may appear more than once.

Target Gmail Account Entity must be set

Cause: A target address is blank in the map.

Fix: Fill in every target user and upload again.

User not found

Cause: A user in the map does not exist, usually a wrong domain or username.

Fix: Correct the map and upload it again.

Mail service not enabled

Cause: Gmail is off for the target users.

Fix: Turn Gmail on for those users, or wait a few hours and retry if it persists.

Error occurred while generating user credential

Cause: Domain-wide delegation is not granted yet.

Fix: Allow up to 24 hours, then run a delta import.

Connection test fails (IMAP)

Cause: Google says the server must use port 993 with IMAPS, accept Google IP ranges, and may need an app password; the user may also be at the server's connection limit.

Fix: Confirm server settings, use an app password in the map where required, and close other IMAP sessions for the user.

FAQ

Questions

Is the data import tool the same as the data migration service?

Google's current help pages describe the data import tool at Data > Data import & export > Data import, and those pages sit at addresses named new data migration service. Older guides use the data migration service name.

Can it migrate from Exchange Server on premises?

Google's data import pages list Exchange Online, not on-premises Exchange. For IMAP servers without a trusted certificate or not reachable from Google, Google points to GWMME.

Does an IMAP import bring calendars and contacts?

No. Google says imports from IMAP, Gmail or Google Workspace move email and label data only. Exchange Online imports can include calendars, contacts and tasks.

How many users can I import at once?

Per import: 100 for IMAP, 1,000 for Exchange Online, 1,000 for another Google Workspace account. Start another import for more.

Sources

Official sources

Vendors change menus and requirements. Confirm on the source before you rely on a detail. Last checked 4 Nov 2026.

Google Workspace Help: Import email with the data import toolGoogle Workspace Help: Import email from an IMAP accountGoogle Workspace Help: Understand email import reportsGoogle Workspace Help: Troubleshoot an email data importGoogle Workspace Help: About the data import toolGoogle Workspace Help: Migrate from IMAP servers to Google WorkspaceGoogle Workspace Help: Import your organisation's data to Google Workspace