Glitchy audio playback

Playback of audio in the time line is full of little pops. These are not on the original audio tracks and do not appear in the renders, so it does seem to be a problem of playback. Any ideas?

thanks

Bruce

[Peter Chamberlain]

What audio I/O device are you using? Is it configured for 48kHz?

Thanks for the advice. I went to the MIDI utility on iMac and checked and the input was already set for 48KHz. Seem, though, just the act of opening the app and checking was enough to reset things, as the sound is working perfectly just now.

bruce