Further to Gdkitty's post, I would check your cloud sync tools if you have any (iCloud, Dropbox, etc.) to make sure it doesn't run in an endless loop. I had one case where Dropbox was attempting to download a rather large file, but there wasn't any free disk space for it. The end result was that Dropbox kept the file in cache, ran out of disk space, deleted the cached file and attempted to redownload the file endlessly.