Hi Guys,
Thought this would help, I recently restored a database from Production to Pre-Production environment.
There was a user missing according to EM, but when I tried to add the user I got the User already exists in current database, message.
I checked the sysusers and the user was there.
The problem turned out to be a bug in EM that was not showing the orphaned user.
When I added the latest service pack this was fine and I could run the orphaned user script.
Regards
Stephen