GWMMO error codes & messages

You can also use Google Workspace Migration for Microsoft Exchange (GWMME) to migrate your Outlook data. 

When using Google Workspace Migration for Microsoft Outlook (GWMMO), you might encounter error codes or messages. 

Try the Log Analyzer

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

Troubleshoot error codes & messages

Error code or message How to troubleshoot
Error 400: invalid_request: The version of the app you're using doesn't include the latest security features to keep you protected. Please make sure to download from a trusted source and update to the latest, most secure version Make sure you're using the latest version of GWMMO. For details, go to Download & install GWMMO.
Can't determine recipient email

Senders, recipients, or address book entries are in a non-SMTP address format and won't migrate. Reformat the address so that it’s in format.

Related topic:

User has not agreed to the Gmail Terms of Service

The user must sign in to Gmail and accept the Terms of Service before proceeding.


Usually indicates a PST file exceeds the maximum size supported by Outlook.

Consult your Microsoft documentation for information about supported PST file size.


You might see this error if:

  • You don’t have privileges to access the PST file being migrated.
  • GWMMO can’t access the PST file. GWMMO requires both read and write access to the file.

Another process is accessing the PST file being migrated or the Outlook profile at the same time as GWMMO.

  1. Make sure that any other MAPI application that can access the profile isn't running at the time of the migration.
  2. Make sure that anti-virus, back-up, or desktop search software excludes PST files from their scans.

A message was skipped because it exceeds the Gmail message size limit. If you want to move the message to your new account, you must do so manually (for example, add the file to Google Drive).

Related topics:


The PST file that is being migrated has an incorrect path. The path specified is a network share (\\servername\share\...) and is not valid.

Copy the PST file to the local drive (usually, C:) and migrate from there.


You might see this error if the user conducting the migration has insufficient privileges to access the PST file or GWMMO is unable to find the file.

Make sure that GWMMO has both read and write access to PST files.


GWMMO is experiencing temporary errors.

Related topic:


You might see this issue if the network timeout registry entries are created with a registry data type other than REG_DWORD. To check the data type:

  1. Using the Registry Editor (regedit), navigate to HKEY_CURRENT_USER\Software\Google\Google Apps Migration\Other.
  2. Check that all entries are Type: REG_DWORD.
  3. If needed, consult your Microsoft documentation on how to change the registry data type.

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