Recently had an issue where Worksite 10 Filesite was remembering a credential even though we had wiped it from the client. Turns out there is some heavy credential Caching in FileSite/Desksite and this is the way you need to clear old credentials : 

1. Stop the iwsingleton.exe process in taskmanager
2. Clear C:\Users\%username%\AppData\Roaming\Interwoven
3. Delete the following Windows Credential in Windows 10