Manual recording starts normally and even saves recordings, but after awhile I am unable to save highlights.
Also plays.TV seems to be enabled still, because I can begin manual recording [via hotkey], and start just recording footage normally but still cannot save highlights.
I'm playing WoW 64bit, on windowed full screen, I am alt-tabbing quite abit, but alt tabbing doesn't break it immediatly or anything.
I'm wondering if it's stopping based on space on your drive. Have you checked to see if your drive is full in both the recording and temp locations?