Often we replace Outlook profiles or just OSTs, but there is a much different step. After making sure there are no Outlook.exe processes running, go to the user’s Windows AppData folder:
C:\Users\<username>\AppData
Look for Roaming\Microsoft\Outlook under there, and rename it to Outlook.OLD. Do the same for Local\Microsoft\Outlook if that’s there.
The results are likely to be different :-) You may possibly, also, not have to create a new Outlook profile after doing this. It seems to cause Outlook to replace files which are being corrupted relatively often. This also fixed some mystery IMAP behavior where sync was reported complete but did not bring in new email.