Kept getting this error with Adobe Reader X. I would launch a PDF and it says “There was an error opening this document. Access denied.”
There was an error opening this document
Follow the steps below to fix this.
Launch Adobe Reader X, go to Edit and then to Preferences.
Click on General, and uncheck the box “Enable Protected Mode at startup”. You will then get a popup window in which you will need to click Yes.
Close Adobe Reader X, and now try opening up a PDF document. It should now open just fine without that error coming up.