Outlook may begin to behave poorly, start generating errors, or you may start receiving messages with errors after trying to forward items. If you experience any of the previous issues, you can rebuild your local Outlook profile to start fresh.

All your mailbox's contents (email, calendar, contacts) are stored in Microsoft Exchange, the email servers, so you won't lose them by following this process - they will simply download again.

The steps below are applicable to the Outlook client and are not for Outlook on the web (OWA).

Follow these instructions from Microsoft:

• For macOS
  
  
• For iOS and Android
  
  
• For Windows 10 and Windows 11
  
  1. If you are able to open Outlook:
     • Create a new local mail profile
  2. If you are unable to open Outlook:
     
     • Type Control Panel into the Start Menu and click to open it.

• • • Type Mail in the Control Panel search box and click to open it.

• • • Click Show Profiles...

• • • Click Add...

• • • Type a name for your new profile and click OK.

• • • Verify your name and email address (they should automatically populate) and click Next.

• • • You should see "Congratulations! Your email account was successfully configured and is ready to use." Click Finish.

• • • Click Always use this profile and use the dropdown to select your new profile name. Click Apply and OK.

• • • Close and reopen Outlook. Outlook will begin downloading your mailbox contents using your new mail profile. The time it takes to finish will depend on the amount of data in your mailbox.
      
      
      • Note: If your mailbox contains a large amount of data, the mailbox sync may take a long time to complete, during which time not all mailbox items may be populated. If you need access to your mailbox while waiting for the sync to complete, use Outlook on the web.
        
        
    •  Configure this new Outlook mail profile with your settings. If you need to remember various settings, switch back and forth between your profiles.
      
      
    • Once you are satisfied that this new profile is configured to your liking, delete the previous profile to save disk space. The contents of your mailbox will be unaffected when you delete this old local mail profile.