Outlook will not load. Windows 11 Outlook classic, Microsoft 365

Update classic Outlook, then repeat Sign in via browser and grant the complete Gmail permission requested for Microsoft apps & services; this directly addresses the Google sign-in and Send/Receive symptoms documented for Outlook for Microsoft 365.^1^

1. Update Outlook and retry authorization

1. If Outlook will not remain open, start another Office application such as Word.
2. Select File → Account (or Office Account) → Update Options → Update Now.
3. Restart Windows.
4. Open Outlook and select Retry on the error window, or Sign in via browser on the notification bar.
5. Sign in to the correct Google account.
6. On Google’s authorization page, select the permission allowing Microsoft apps and services to read, compose, send, and permanently delete Gmail mail, and then select Allow.

The built-in Retry flow requires Current Channel Version 2412 Build 18324.20168 or later. Check the installed build under File → Office Account → About Outlook.^1^

2. If browser sign-in still fails, reset only the Gmail authorization

This removes the saved Google authorization, not the Gmail messages stored on Google.

1. Close Outlook.
2. In a browser, sign in to the affected Google account.
3. Open Manage your Google Account → Security.
4. Under Your connections to third-party apps & services, select Microsoft apps & services.
5. Select See details → Remove all access → Confirm.
6. In Windows, search for and open Credential Manager.
7. Select Windows Credentials, then scroll to Generic Credentials.
8. Find entries beginning with MicrosoftOffice16_Data:OAUTH2.
9. Expand or hover over each entry and identify those containing tp_google_imap_Oauth2.
10. Remove both matching credentials for the affected Gmail account.
11. Reopen Outlook, select Sign in via browser, and grant the complete mail permission described above.^1^

If the account was removed from Outlook, add it through File → Add Account, enter the Gmail address, and complete the same browser authorization.

3. If Outlook itself does not open

The Google authorization error and an Outlook startup failure should be treated separately. First try launching Outlook in Safe Mode:

1. Press Windows+R.
2. Enter outlook.exe /safe and select OK.
3. If Outlook opens, perform the update and Google authorization steps above.

If Safe Mode also fails, provide the exact startup error separately; the Gmail known-issue procedure addresses account authentication and synchronization, not every cause of Outlook failing to launch.

Additional conditional checks

• If the browser displays “Could not sign you in to Google”, open File → Office Account → Account Privacy → Manage Settings, enable Optional connected experiences, restart Outlook, and retry. Microsoft documents this for Outlook for Microsoft 365, Outlook 2021, and Outlook 2019.^2^
• If Outlook signs in successfully but Gmail folders still do not synchronize, verify that Gmail’s IMAP access and the required folders are enabled for IMAP. Synchronization can take up to 15 minutes after those settings are changed.^3^
• Use Gmail in a browser while repairing Outlook so email remains accessible.

References

1. Unable to add a Gmail account to classic Outlook | Microsoft Support
2. Unable to add a Gmail account to Outlook "Could not sign you in to Google"
3. Fix problems connecting your Google account to the Microsoft Cloud