I started to deploy Adobe Reader X to one of my clients the other day and found that users were unable to open files on shared drives mapped to our DFS. Searching through the web I found the following KB article from Adobe (http://kb2.adobe.com/cps/860/cpsid_86063.html)

Cannot open PDF files whose source is DFS or NFS: PDF files in shared locations on a distributed  or networked file system (DFS/NFS) cannot be opened. Attempting to open such a file results in an error opening this document. Access denied.”

Initially I thought I would have to remove Adobe from all the workstations however a quick look in the registry found the place where this has been set – HKEY_CURRENT_USERSoftwareAdobeAcrobat Reader10.0Privileged. To get around the problem I added the following to my login script to force the “bProtectedMode” value to 0

reg add “HKCUSoftwareAdobeAcrobat Reader10.0Privileged” /v bProtectedMode /t REG_DWORD /d 0 /f

This is definitely one to watch out for if rolling out Adobe Reader via GPO.