Hi- I had this working then it magically stopped about a year ago and I can't get it back. When I try to open a pdf I get "...could not be opened, because an unknown error occurred. Try saving to disk first and then opening the file." I have gone into settings and re-selected adobe acrobat and restarted but still can't open. I am on a mac. Thanks for your help! Crazy frustrating and time wasting issue.