Quote:Microsoft says in a support document recently published that Outlook will fail to start for some users, automatically displaying an error prompting the users to repair some inbox files.

According to the company, all users who have updated Outlook to version 2005 Build 12827.20268 or higher will see an error prompt saying that "Something is wrong with one of your data files and Outlook needs to close. Outlook might be able to fix your file. Click OK to run the Inbox Repair Tool."

Microsoft lists this known issue as being caused by the June 2020 updates on a support page with fixes and workarounds for recent issues affecting Outlook for PC.
 

Outlook error (Microsoft)

After Outlook users click the "OK" button, the Inbox Repair Tool launches and walks them through the repair process.
The next step is to reboot the computer to apply the fixes and, hopefully, have the issue resolved but, instead, Outlook will again display the same error as Woody Leonhard points out.