For weeks now I have had a machine that every time you opened Acrobat v8 would ask for the administrator password. This would only happen under a non admin account. It was getting very annoying.

After speaking to my contact at Adobe he got me through to 3rd line support. Below is the answer he gave me. It is worth noting that once you have this error the fix below will only work if you uninstall Acrobat and then re-install it. The uninstaller is in the Acrobat folder.

There are three files that are installed on the second launch of Acrobat. If the second launch is from a non-admin user then he will get an authentication dialog. If the second launch is from an admin user then there is no prompt and from this point on any non-admin user can launch without the need to authenticate.

So the solution seems to be to launch Acrobat as admin twice before launching as user. Obviously this is not ideal and this issue will be addressed in a future Acrobat update.