Are you in a network in which another person might be working on the same file? Is "Always create a backup copy" ticked in Tools menu>Options>Save? How long is the filename of a document that behaves like this, including the full path?
I am having the same issue. Sometimes when my users are trying to save a document from Office whether it be excel or word or even a pdf for that matter it says the user doesn't have the right permissions and then they try it again and it works fine...I am using windows 7 pro on a network and the user has admin rights on the machine and the permissions are correct on the share for security and shared permissions. I did try disabling Offline files, it worked for a little while, but now they are popping up again. Has anyone else had success???
Because the events are occuring randomly, it could be a virusscanner or something that locks access to the file temporarily when it's being scanned. You could check it's settings if it's actively protecting files in use or something.
I had tried all of the 'Take Ownership' style 'fixes' that I could find. Some would work temporarily, then revert back to the error, and some wouldn't work at all. Last night I stumbled across a thread on another site regarding 'icalcs' which is a Windows utility that edits ACLs (access control lists).
Long story short, I started running this utility via CMD prompt on my 1TB USB 3.0 drive and after an hour, went to bed. When I awakened, the utility had finished after processing nearly 400,000 files and my permission error problems are gone!
However, many readers were having problems running the utility (not sure why), so I created a .BAT file that does it for you. Simply place the .BAT file in the directory to have its permissions reset, and run the file as an administrator.