FIX: Pro Tools Audio Device Buffer Underflowed

The Error Message

The audio device buffer underflowed. If this occurs frequently, try decreasing the “H/W Buffer Size” in the Playback Engine panel or remove other devices from the audio firewire bus. (-6085)

Occasionally this error pops up in Pro Tools, usually after I return from a meal in the middle of a long recording or mixing session. The session file will only playback audio for 1 second or less and then the error message pops up. Apparently, Pro Tools 9 is a workaholic and doesn’t like taking lunch breaks, at least when running on the particular combination of MacBook Pro, Mbox 2 Pro, and Western Digital hard drive that I’m using.

Following the directions to decrease the “H/W Buffer Size” in the Playback Engine panel doesn’t seem to help. In fact, not only does decreasing the buffer size seems contrary to the suggested way to solve a buffer underrun, but it then sometimes throws this error message:

A CPU overload occured. If this happens often, try increasing the “H/W Buffer Size” in the Playback Engine Dialog, or removing some plug-ins. (-6101)

The Fix

I’ve tried a lot of things and the problem seems to be related to the hard drive and firewire ports. Here’s how I fix it.

1. Save and Close the session.
2. Quit Pro Tools.
3. Eject the hard drive used for recording audio.
4. Unplug the audio hard drive and Mbox 2 Pro (or the audio interface you’re using).
5. Wait 10 seconds.
6. Reconnect the audio hard drive and audio interface.
7. Restart Pro Tools.
8. Reopen the session and press Play.

If the session plays back without stopping, then it worked. If not, then I don’t know what to tell you, which reminds me of a “Deep Thought” by Jack Handey.

If you ever crawl inside an old hollow log and go to sleep, and while you’re in there some guys come and seal up both ends and then put it on a truck and take it to another city, boy, I don’t know what to tell you.

Hopefully this solution worked for you. Let me know if you’ve had the same problem, what hardware you are running and if this solved the problem.