WIndows User Profile corruption - Windows 2008 Server, Vista, Windows 7

Windows 2008 user profile got corrupted by perhaps a network problem or unplanned server reboot.

The issue can happen on Vista and Windows 7 as well, you can find the same registry "profilelist" file structure.

When the user attempted to login he was prompted that the profile was bad - the server was inaccessible to his account.
The profile list is in the following location:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\ProfileList\

The issue is that there are two SID files of the same name.
One with a .bak extension and one without.

The one without the extension, pointed to:
C:\Users\temp
The .bak SID, pointed to the original user profile, example below:
c:\users\username

example:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList\S-1-x-xx-xxxxxx...-xxx.bak

The temp profile only had 3 keys as opposed to the 7 keys the former profile had - and still has after removing the .bak extension.
* The final step is to change the state property of the SID set to Zero.

This can happen on Vista and Windows 7 as well!

You can prevent your computer from being inaccessible by creating a second user on the computer in Control Panel > Users, so that you can log in with a good user profile, then edit the other profile.
The issue is rare, and you may never need it - good prevention on the outside chance that you run into this issue.