Shockingly, you can delete all your profiles and even uninstall, reboot, and reinstall Outlook and still have nasty issues that linger.
Some stuff that will not be reset includes....
- Any VBA scrips
- Any ribbon bar customizations
- The database of which emails have already been downloaded via POP3
...and lots of other stuff that can haunt you.
To completely reset Outlook, you must....
- Uninstall the Outlook application
- Delete all the profiles
- Delete the tree under the registry key
[HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office]
(or you can go in and only delete the sub-trees for your Outlook version if you want to keep state for other Office applications)
- Delete (or rename to a .bak) the folder
C:\Users\[your user name]\AppData\Local\Microsoft\Office
or %localappdata%\Microsoft\Office
- Delete (or rename to a .bak) the folder
C:\Users\[your user name]\AppData\Roaming\Microsoft\Office
or %appdata%\Microsoft\Office
- Delete (or just don't use) the previous PST file.
I only know all this because I had a nasty problem where Outlook started downloading messages over POP3 and then deleting them. Deleting all profiles, PST files, and uninstalling/reinstalling did not solve the problem. Only after following all the above steps did the problem go away. I still can't figure out exactly where the POP3 messages database is actually stored.
Can't you create a new account and then delete that last one which you weren't allowed to get rid of earlier? – Karan – 2013-03-29T08:16:31.570