VGA drops to 640 x 480 resolutionafter RDP session

Thanks Tsmvp but RDP client is already version 6 and latest VGA drivers. That was the first thing I tried.
Only started in the last week. RDP update was WSUS as soon as it came out and VGA drivers were updated two months ago and there are no updates.
Olaf

On whose machine does the resolution go back to 640x480? On the rdp session or on the client's machines after they've logged out from the rdp session?
is it affecting just these two machines or other machines as well?

It's affecting two machines in one site and one machine in anotherso far.
It's affecting the target workstations. When they return from the outside world (hence the RDP) their workstations in the office are sitting at the: This machine has been locked... at 640x480 resolution.
When they logon it stays at 640x480 resolution till you change it manually or restart.
Olaf

No, this is based on client reports.
I have only seen it once myself. Eventlog was clean at the time and I just restarted to get the client going again.
I do know that except for Automatic Updates from WSUS nothing has changed.
I was just wondering if someone else has had similar issues.
Olaf

Further update: Only happens if user is logged on at the local workstation at work and logs on remotely too.
Only fix is a restart of the workstation.
Olaf

This is still happening. Only when same user logs on to his/hers open profile at work.
Happens on 3 of the 25 SBS I administer.
Any ideas anyone?
Olaf

I think I have a possible answer: Only happens to users with a large amount of files or large files on the desktop.
If I clean the desktop it does not seem to happen.
Possible?
Olaf

Thanks for helping out. I have now proven that big files on the desktop cause the problem but thanks for stearing me in the right direction and taking the time to help out.
Olaf