We have a Windows 2008 Server running with shared folders and some users with different permissions.
My problem is that some day, without changing anything in the server, a certain user started having problems connecting to any of the shared folders, but could use a system that connects to the SQL databe running on it. I tried logging with my user and everything worked fine. So I created a new user, granted all the required permissions and so on. All access was granted again as supposed to be.
After a while, the same problem appeared, windows explorer displays an error such as "username not found". But I can access all other computers on the same Domain.
Both users that are now being denied access on that particular machine dont have that problem if I log with them in other machines.
So I figure it has nothing to do with ActiveDirectory in the server, but rather something specific in the machine in the config of those users that somehow change.