Hi,
Sorry to hear about this, during development I have stress tested this a lot and we fixed all these kind of crashes. I just had a try at dragging and dropping presets and entire banks like a maniac and everything seemed stable (OSX 10.12.6)
Can you give me more details about your setup ? (EG how the MatrixBrute is plugged, with a USB hub or not)
Here are a few basic troubleshooting steps to try out to help you pinpoint the issue :
-Make sure your MCC is up to date ( 1.7.1.554 )
-Try another USB Cable
-Try another USB Port
-Try removing other USB devices from your computer
Hope this helps