It's totally unpredictable. Sometimes it will playback, other times it crashes when i click the mouse. it even crashes when i move the mouse. A few moments ago i was able to move the slider, then it moved on it's own. then i was able to playback. and now it totally won't let me do anything at all.
This was working fine until yesterday. Was editing comfortably, no problems.
I tried to retrace my steps, all i changed to my mac yesterday was I installed audacity. but the initial crash happened when i dragged and dropped a 28 GB MPEG-4 movie and was in the middle of conforming.
i have a brand new mac with 16GB of ram and running OS X El Capitain version 10.11.2
I can tell you that from my experience, Audacity caused all sorts of problems with my PC system. I can't tell you any specifics, other than that once I uninstalled Audacity, everything went back to stable. And this was on a system with CS6.