Playback Engine scrambled. Plays stereo track out of sync

[aasteveo]

Yesterday I ran into a bazaar Pro Tools freakout where it suddenly plays a stereo track out of sync.
I'm on Pro Tools 9, Snow Leopard, HD3 rig, Big Ben clock, 96k.

We have a session with a two-track drum stem, and out of nowhere the right side of the track would play like 50ms later than the left. Even the meters on the track would look out of sync on a single snare hit.

The engineer said he's seen this before and explained that the Playback Engine just gets scrambled sometimes. We shut down the rig, rebooted, and everything worked. It happened again today, with a different song. Same thing, rebooted, and it was fine.

I want to know what causes this and what I can do to prevent it. Anyone experience this?

[albee1952]

Trashing prefs is step #1 for odd behavior, and this certainly sounds odd to me. After that, maybe the session is corrupt(is this a particular session or any/all sessions??). One solution to that; create a new session at a different sample rate(IOW, if the old session is 48K, make the new session 44.1K). Then import session data from the troubled session. The sample rate conversion re-writes all the audio files and this has saved a screwed up session for me 2 times. No promises, but its worth a shot

[aasteveo]

Didn't happen today. Now that I think back, I'm not sure if the second time it happened was on the same song or not. Maybe it was just one song that got corrupt. We've been working off multiple drives and importing session data a lot. I'm gonna keep my eye on it and see if it happens again. Such a strange phenomenon.