Distorted playback after switching audio engines

[cjansson77]

Hi there, hoping someone can help me get rid of this ever-reappearing distorted playback.

I'm using PT11 on a fairly new Macbook Pro, running OS X 10.9.5 w/ a 2.8 GHz i7 Intel core and 8 GB of memory. I recently moved and am in the process of re-setting up my equipment in my new location. Here's the deal:

I started a new session a few weeks back without having my audio interface or any microphones--the session is purely made up of virtual instruments. I have about 30 tracks, with 2-3 plugins on most of the tracks, and my Mac has been playing the session back with absolutely zero problems. So I know the buffer size/number of tracks/plugins isn't an issue, because my laptop is more than capable of playing back the session with its own audio card.

HOWEVER, I just unpacked my interface (M-Audio Fast Track Pro) and plugged everything in, looking forward to recording real audio for the first time in weeks, but the second I change the playback engine to the Fast Track Pro, the playback becomes distorted. If I change the playback engine back to "built-in output," the distortion disappears and I'm back to where I was. I've tried changing the buffer size but this does nothing. Ideas?

Thanks in advance,
Chris

[Shan]

Are you using the most recent Fast Track Pro driver?

Shane