Phantom Drive Letter

Weird one got a Phamtom drive letter for one out of 7 win2k users on our site.

The drive letters get mapped by the login script and work on all 6 other machines.

It currently show a drive letter and a red x through it.

If you type net use no drive letter shows.

If you try to create a drive useing the same letter in this case h: you get an error resource in use.

Any ideas?