We have been running Adobe Acrobat on a Terminal Server for over a year and have just encoutered this problem. All of the non-administrative users that log into Remote Desktop and try to run Adobe Acrobat Standard 8.0 get the following: "No Valid Acrobat Serial Number. Acrobat will now Quit" I have unintalled and re-installed using Add/Remove Programs and running the setup executable, but it still gives me the same message. When I log in as myself (administrator) it runs fine. I have tried to add users to permissions, but it still did not work. I'm at my wits ends. Has someone run across this before?