Access gmail using Outlook Classic

Hi! Sorry to hear that you're having trouble with this situation. Could you please let me know what happens when you try to use Gmail in Outlook Classic? Do you get an error message or an error code? If so, please share a screenshot of it.

This is a known issue affecting Gmail accounts in classic Outlook and is related to recent changes in Google authentication and Outlook’s sign-in flow.

Use the following steps depending on the situation.

1. Confirm Outlook build has the fix The issue “The browser or app may not be secure” or “We weren’t able to set up your Google account with IMAP…” has been fixed in newer Outlook builds by changing sign-in to a separate browser window.

Check that classic Outlook is on one of these or later:

• Current Channel / Current Channel Preview / Beta Channel: Version 2404 (Build 17531.10000) or later
• Monthly Enterprise Channel: Version 2407 (Build 17727.10000) or later

If Outlook is older, update it:

• In Outlook: File → Office Account → Update Options → Update Now.

If you previously switched to an Insider channel as a workaround, use the same documented registry-based method to switch back after updating.

2. If Gmail stopped syncing or can’t be added, apply the Gmail/credential workaround If updating does not immediately fix access, reset the Google authorization and cached credentials, then re-add the account.

Step 1 – Remove “Microsoft apps & services” access in Google

1. Close Outlook.
2. Sign in to the Gmail/Google account at https://www.google.com.
3. Select the profile picture → Manage your Google Account.
4. Go to Security.
5. Under “Your connections to third-party apps & services”, select “Microsoft apps & services”.
6. Open the details for “Microsoft apps & services has some access to your Google Account”.
7. Under “Access you’ve given to Microsoft apps & services”, choose Remove all access and confirm.

Step 2 – Remove old Google IMAP OAuth credentials from Windows

1. Open Credential Manager (Start → search “Credential Manager”; on Windows 10 you may need Control Panel → Credential Manager).
2. Select Windows Credentials.
3. Under Generic Credentials, find entries starting with MicrosoftOffice16_Data:OAUTH2.
4. Expand each and hover over the name to see the full value including tp_google_imap_Oauth2 – these are the Gmail credentials.
5. Remove each MicrosoftOffice16_Data:OAUTH2 entry associated with Gmail (there are typically two per Gmail account).
   • To target only one Gmail account, map the credentials to identities under: Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity\Identities in Registry Editor.
6. Re-add the Gmail account in classic Outlook
7. Open Outlook.
8. Go to File → Add Account.
9. Enter the Gmail address → Connect.
10. When the Gmail sign-in window opens, confirm the address → Next.
11. Enter the Gmail password and follow the prompts.
12. On the Google permissions window, select Allow.
13. Finish the wizard.

If Outlook reports “Something went wrong”, choose Retry and complete the prompts again.

4. If Outlook won’t accept the Gmail password On older Outlook builds that don’t support the newer Gmail flow, Gmail may require either:

• Two-factor authentication plus a Google app password for Outlook, or
• Enabling “less secure apps” (not recommended).

The recommended approach is to enable two-factor authentication on the Google account and create a Google app password specifically for Outlook, then use that app password when configuring the account.

5. If classic Outlook never prompts for a password when adding IMAP If using manual IMAP setup and no password prompt appears:
6. On the IMAP details page, ensure “Require logon using Secure Password Authentication (SPA)” is unchecked.
7. If still failing, configure via Control Panel → Mail → Email Accounts → New, then follow the automatic setup and enter the password when prompted.

References:

• Unable to sign in or add a Gmail account to classic Outlook
• Unable to add a Gmail account to classic Outlook
• Add a Gmail account to Outlook for Windows
• Troubleshoot Outlook email setup
• gmail accounts no longer working in outlook classic - Microsoft Q&A
• search for solutions another user has found - Microsoft Q&A