In Acrobat Reader X we have run into a problem where we get an error message when we try to open files from a file share. We get an access denied error.
Here is how to fix it:
1. Open Acrobat Reader X
2. Click on Edit -> Preferences
3. On the General Tab uncheck Enable Protected Mode at Startup
4. On the Security Enhanced tab uncheck Enable Enhanced Security
5. To disable Protected Mode via Registry Key
Enter this at the command line:
REG ADD ”HKCU\SOFTWARE\Adobe\Acrobat Reader\10.0\Privileged” /v bProtectedMode /t REG_DWORD /d 0 /f
via Adobe Acrobat Reader X ”Access Denied” – Spiceworks Community.

