When I 1st got my computer a year ago, I had quite a few problems with that, even on the very first day. I just hit the spacebar 2x quickly and it'd be ok.
 
I had a lot of instability, but after lots of hard work and tweaking I have a very stable computer and haven't seen that error in about 6 months or so. I'm not sure what caused it either

ok I think I found out what was the problem. It seems sonar doesn't like a really long projects and shows some random issue like general error or moving the midi notes to left and right after input a new velocity and make the notes out of the sync. I realized these issues just show themselves on the long projects which mine was 45 minutes .
I replicated another long project by adding some waves and problem showed again.
 

What GMP says.