Over the last few weeks, some recordings started to fail on me. The thumbnail would be blank, playback would result in choppy sound and no video. Turns out this happened every time two recordings were scheduled back to back on the same channel. The first one would record, the second one would fail. If I caught it, I'd be able to "fix" it by cancelling the recording, changing channels, changing back, and then starting the recording again. Hardly a fix.
After looking at my event log, I started noticing a strange pattern in the System log (although there were also "SqmApiWrapper.TimerAccumulate failed" messages in the Media Center log). About one minute before the first recording is about to end, there would be a message "Automatic Updates is now paused.", and then about a minute later, almost exactly when the first recording stops and the second begins, a message "Automatic Updates is now resumed." The source on both is WindowsUpdateClient, and it's Event 27 and 28 respectively.
So, naturally I stopped the automatic windows updates (which weren't scheduled to run anywhere near the recording time) and the problem has now gone away. No automatic updates, but I'd rather have my recordings.
This is a single cable card tuner system.
So, problem solved for now, or at least a workaround. But I'm wondering if anyone else has this problem or has any insight on the true nature of it. I've seen other "back to back" isues, but all have dealt with multiple tuners.