After having installed a software on my Windows 2003 terminal server, no user has been able to launch applications anymore.
When they log to the server via remote desktop, each icon they click produces the message "there is no application associated to this file". Even "My Computer" or other default links.
After a lot of research, I discovered that the:
HKEY_LOCAL_MACHINE\SOFTWARE\Classes(all the sub-entries)
miss the "users" item in the permissions ACLs (see the screenshot below).
Infact, administrators aren't affected by the problem and regular users that get included into local administrator groups work correctly again.
Then i discovered an even more worrying fact.
In order to do some test, i've tried to manually assing to one of these subfolter the access for a regular user, and it worked, e.g.:giving access to the "Folder" entry, the user gets access to the "My Computer" item
But if i try to remove it, the system says that i can't because it is inherited by the parent!
So the propagation from parent to sub-items seems to be corrupted here.
Any idea of a way to fix it?