If end user is getting a credential pop-up window for someone else's credentials, but you can close out of the window and continue using Outlook (cred window should come back up constantly)

> path to the .pst file
C:\Users\USERNAME\AppData\Local\Microsoft\Outlook
> renamed .pst file to "first.last@msmc.edu_OLD"
> reopen Outlook

This should re-create their profile and resolve any of the credential issues

*******

If end user is getting a credential pop-up window for someone else's credentials, AND Outlook will not open

> Control panel
> Mail (Microsoft Outlook 2016)
> Email accounts
> search for any "email/data files" other than the end user's, and REMOVE

Restarting Outlook should work now