A likely cause is that Outlook is still referencing an invalid data-file location from the old profile, especially after OneDrive was involved. Active Outlook PST and OST files should not be stored in OneDrive-synced locations.
Recommended path:
- Close Outlook completely.
- Open Control Panel > User Accounts > Mail > Show Profiles.
- Select the existing Outlook profile and remove it.
- Warning: removing a profile can remove associated offline data files. If there is any PST data that still matters, back it up first.
- Select Add to create a new profile.
- Enter a new profile name.
- Enter the account details and complete setup.
- Set Outlook to use the new profile, or choose Prompt for a profile to be used.
- Start Outlook with the new profile.
If Outlook starts normally after that, the old profile was corrupted.
If the profile is created but Outlook still fails, repair the Outlook data files with the Inbox Repair Tool (scanpst.exe). Exit Outlook first, then use the repair steps in the Outlook data file repair article.
If the issue is specifically with the mail connection after profile creation, Outlook also has a built-in profile repair path:
- In Outlook, select File.
- Select Account Settings > Account Settings.
- On the Email tab, select the account and choose Repair.
- Complete the wizard and restart Outlook.
For the OneDrive part of the problem, the supported fix in similar cases is to stop using the old OneDrive path and rebuild the Outlook profile so it points to a local, non-synced location.