Troubleshoot a Microsoft Outlook migration

Google Workspace Migration for Microsoft Outlook

If you encounter a problem with Google Workspace Migration for Microsoft Outlook (GWMMO), first check the system requirements. Then, troubleshoot your migration using the common issues below.

Try the Log Analyzer

This tool can identify most issues within a few moments of submission. 

Where do I find the logs?

You can find trace files for your imports here:

  • Microsoft Windows 7 and up—C:\Users\your-user-name\AppData\Local\Google\Google Apps Migration\Tracing\ClientMigration.
  • Earlier versions of Windows—C:\Documents and Settings\your-user-name\Local Settings\Application Data\Google\Google Apps Migration\Tracing\ClientMigration.

Troubleshoot common issues

Open all   |   Close all

Some or all of my data isn't importing from my old account

Here are some steps to troubleshoot this problem:

  • Check you're connected to the web during the migration and that you're not experiencing network connectivity issues.
  • Make sure Outlook is closed during the migration.
  • Don't import from an OST file. GWMMO supports importing only from a PST file or directly from an Exchange account. Learn more.
I'm getting duplicate contacts after importing

This happens when you import contact data multiple times into the same Google Workspace account. Import your contacts only once. If you do end up with duplicate data, do one of the following:

  • Delete all your personal contacts from your Google Workspace account. Then, use GWMMO to reimport your contacts.
  • Remove duplicate contacts manually from Google Workspace.
I'm getting the error "One or more items failed to import". Does the rest of my data continue importing anyway?

Yes. The rest of your data will continue importing unattended. If your migration wizard is still open, you can open the Migration log file from the wizard's progress screen to view a list of errors. Otherwise, find your trace log files here:

  • Microsoft Windows 7 and up—C:\Users\your-user-name\AppData\Local\Google\Google Apps Migration\Tracing\ClientMigration.
  • Earlier versions of Windows—C:\Documents and Settings\your-user-name\Local Settings\Application Data\Google\Google Apps Migration\Tracing\ClientMigration.
Certain classes of messages (read receipts, delivery/non-delivery reports) aren't being imported

GWMMO currently doesn't migrate certain message classes, including read receipts and delivery/non-delivery reports.

Migrating large messages can time out over a slow connection

If you import a message with large attachments (multiple megabytes) over a slow connection, the connection can time out. After multiple retries, the migration stops and you'll see the Windows Update error code 80072ee2 in the log files.

By default, the connection timeout is 120 seconds. You can extend this period to accommodate messages that take longer than 120 seconds to migrate by modifying your Windows registry. Specifically, add the following keys to override the default timeout values:

  • HKEY_CURRENT_USER\Software\Google\Google Apps Migration\Other\ResolveTimeoutSeconds > DWORD Value = 00000030
  • HKEY_CURRENT_USER\Software\Google\Google Apps Migration\Other\ConnectTimeoutSeconds > DWORD Value = 00000030
  • HKEY_CURRENT_USER\Software\Google\Google Apps Migration\Other\SendTimeoutSeconds > DWORD Value = 00000600

The example values above give timeout periods in seconds, and can be adjusted to accommodate your connection.

How do I add these keys to my registry?

  1. In the Start menu, click Windows System and then Run.

    Note: Alternatively, press the Windows key + r.

  2. In the Run box, specify regedit.

    Note: If you're running a 32-bit version of Outlook on a 64-bit version of Windows, you need to add these registry keys in the correct location for 32-bit applications. For details, go to Using a 32-bit version of Outlook on a 64-bit version of Windows.

  3. In the registry, go to HKEY_CURRENT_USER\Software\Google\Google Apps Migration\.
  4. Click Edit and then New and then Key to create a new key folder.
  5. Specify Other as the name of the key, and press Enter.
  6. Select the Other folder you just created.
  7. Click Edit and then New and then DWORD (32-bit) Value.
  8. Specify ResolveTimeoutSeconds as the new value, and press Enter.
  9. Right-click the ResolveTimeoutSeconds value you just created and select Modify.
  10. In the Edit DWORD (32-bit) Value box, under Value data, specify your desired timeout value (00000030, in our example above).
  11. Click OK.
  12. Repeat steps 6–11 to create a DWORD (32-bit) Value for the other two timeout registry keys listed above:
    • ConnectTimeoutSeconds:
      • DWORD (32-bit) Value—ConnectTimeoutSeconds
      • Value data—00000030
    • SendTimeoutSeconds:
      • DWORD (32-bit) Value—SendTimeoutSeconds
      • Value data—00000600
How do I turn on different logging levels?

To turn on different logging levels (Information, Verbose, or Performance) for GWMMO, edit the Tracing registry key folder and its accompanying REG_DWORD value.

  1. In the Start menu, click Windows System and then Run.

    Note: Alternatively, press the Windows key + r.

  2. In the Run box, specify regedit.

    Note: If you're running a 32-bit version of Outlook on a 64-bit version of Windows, you need to add these registry keys in the correct location for 32-bit applications. For details, go to Using a 32-bit version of Outlook on a 64-bit version of Windows.

  3. In the registry, go to HKEY_CURRENT_USER\Software\Google\Google Apps Migration\.
  4. Select the Tracing folder.
  5. Right-click the Level value and select Modify.
  6. In the Edit DWORD (32-bit) Value box, under Value data, change the default value of 7 to one of the following hexadecimal values:
    • f—Information
    • ff—Verbose
    • 4F—Performance
  7. Click OK.

Note: Verbose logging can generate large log files, which can impact performance and the availability of disk space.

Why is there a difference between the total number of messages following a migration?

Following a migration, you might notice the number of email messages in the source environment exceeds the number of messages migrated to Gmail.

This discrepancy might be due to the difference between folders in Exchange and IMAP mail servers and labels in Gmail. In Exchange and on IMAP mail servers, when you assign a message to more than one folder, the message is duplicated. Following a migration, the duplications are removed in Gmail and different labels are applied instead.

To verify all messages have been migrated, check the logs for any errors. For details, go to Monitor a migration.

If you believe you’re missing some messages, check whether:

  • The message, including attachments, is not bigger than 25 MB. You can’t migrate messages bigger than 25 MB. For details, go to Send attachments with your Gmail message.
  • Gmail has not blocked an attachment to the message. Gmail blocks certain types of attachments, such as executable files. For details, go to File types blocked in Gmail.
  • The message is in a folder or within a date range that’s part of the migration.

If you think some labels weren't migrated, check whether the trace log files contain the information message Skipping hidden folder. If listed, it means the folder in the source account is invisible.

I'm getting the warning "User neither attendee or organizer for event"

This happens when you import events for users who are not an original organizer or initial attendee for the event.

Regardless of the warning message, the event successfully migrates into Google Workspace and the Google Workspace target user is shown as an attendee of the event on the Google Calendar. This is necessary as Google Calendar doesn't support listing calendar events for a user where they aren't an organizer or attendee.

Do I need to allow traffic from permitted URLs?

If you experience network-connectivity issues, you should approve the following URLs:

URL Purpose
https://oauth2.googleapis.com/token
https://www.googleapis.com/oauth2/v4/token
Authentication
https://www.googleapis.com/calendar/ Calendar
http://crl.geotrust.com/crls/secureca.crl
http://g.symcb.com/crls/gtglobal.crl
http://pki.google.com/GIAG2.crl
http://g.symcd.com
http://clients1.google.com/ocsp
Certificate Revocation Lists
https://www.google.com/m8/feeds/contacts/ Contacts
https://mail.google.com/mail/r/
https://www.googleapis.com/gmail/
Mail

 

Note: If you're using a Windows parental control system, you might need to add URLs to your allowlist. For details, consult your Microsoft documentation.

Review how to find Google IP address ranges. GWMMO can use any one of these IP addresses.

For details on current CRLs, go to CRL check.

Are there other known data migration issues?

There might be. For details, go to Google Workspace Known Issues and look under Data migration and sync.


Google, Google Workspace, and related marks and logos are trademarks of Google LLC. All other company and product names are trademarks of the companies with which they are associated.

Was this helpful?
How can we improve it?