For some unknown reason I was having a hard time opening PDF files on my machine (Windows 8.1).
I updated the Reader, I restarted my machine - in other words tried all the simple things that would come to mind. After some googling around I found out that there is a service that needs to be running to make that happen - Remote Procedure Call (RPC) locator. It should be listed as manual and it should be running. Mine wasn't. Turned it on. Problem solved.
I am not fully sure how RPC is related to PDF's but it is possible that there are issues with application compatibility.
