We have a lab full of powerful Macs that have the latest DP (7.24), plus VSL. A certain percentage of the time, after a number of tracks are added (and instruments are added to Vienna Ensemble), users get crackling and can't get rid of it. Sometimes it is a constant low-volume crackle, sometimes pretty loud and sporadic.

Occasionally, re-connecting the Vienna instrument will work. I tried Maya's solution (above) using "default to real time" and/or "run this instance in real time." ("Always run in real time" -- those exact words -- did not appear in any DP menu I could find; please let me know if we missed it). I made sure to quit and restart the program each time. No luck. Crackling persists. Any other ideas?

People are resorting to using other software synths to complete projects. But not everyone has the problem. Quite perplexing.