Release.exe is part of McAfee as Mr Mistoffelees suggested.
It would appear that it was previously installed on your PC and then uninstalled using Windows uninstaller. Unfortunately because of the nature of anti virus software it is deliberately hard to remove for obvious reasons.
The only way of completely removing it is to download the uninstaller from McAffee here.
Sorry, ignore my previous post, brain not in gear, however, whatever is causing the message should appear in processes so it still may give you a clue especially if its coming from a routine you recently uninstalled.