not sure what's happening here, but every few minutes Sonar is crashing on a particular project file that up until recently was working fine. AFAIK other projects are fine. I don't think it's a plugin causing the crash because the same plugins are present on most of my other projects. 

Running windows 8.1 64 bit with Sonar 8.5.3 32 bit. Thanks

EDIT:

it's not an actual crash, Sonar just freezes up and stops responding and eventually closes. I don't think any crash logs are being saved, as it's not asking if I want to save the file like it does during a standard crash.

I have verified that it is indeed only that project file. I've been working for several hours on other songs and they're working just fine. VSTs and everything.

Does it happen during playback, or just sitting there in edit mode? If only during playback, does the hang occur at the same spot each time?
 
Does the green audio engine indicator go dark, or the "engine stopped" indicator at the bottom come on?
 
Even if you don't suspect a plugin, if the hang is consistent enough it'd still be a good idea to try playing back the project in global bypass (ctl-shift-Y) and see if that stops the hangs. If it doesn't, try bringing up the project in safe mode (hold SHIFT down while loading).

happens while in edit mode. I haven't noticed the audio engine shutting off. I'll give that a shot, thanks