ADR / Looping crashes constantly

Hello,
 
I'm trying to use Sonar to record some ADR. It's a simple project, one video file, the audio from that video file, and the track I'm using to record one microphone.
 
I set my loop points, arm the track, and hit record.
 
Sonar seems to hang while it's recording. The screen freezes, and the software crashes. I lose the audio file (the last series of takes) and have to reload from my last save / autosave.
 
I've tried using MP4 (H.264 codec), WMV, and DV AVI files with no luck. Sometimes, when it works for a while, it pauses momentarily every time it goes back to the start of the loop and then eventually crashes again.
 
I'm not sure what to do. I've also tried recording to 3 different drives: the mSATA system drive, the internal HDD, and an external 2xHDD raid array configured for speed.
 
Any ideas? Some kind of bug? I used to loop like this in the older versions of Sonar with no issues. The SaaS version seems a little less stable in general to me, but I admit that might be a system configuration issue I'm not aware of or something.
 
Thanks so much!
 
Here's my specs:
MSI GT72 2QE laptop (fairly new, January 2015)
i7-4710HQ @ 2.5 GHz 4/8 cores
16GB Memory
GTX 980M vieo card
Windows 10 Home
Sonar Platinum (I've tried it with the last few updates with no improvements)
Focusrite Sapphire 18i20 via USB3.0