Hi on certain occasions especially when I am editing Midi in Session Drummer Piano Roll my system suddenly starts looping a few notes. I use VS100 interface in a W7 x64 system. The project has both audio and midi tracks and it happens during play back and sounds like a very short loop.
To get out of it I only can restart my computer. I also can switch off and switch on my interface but then I still have to restart as Sonar crashed and won't restart anymore.
Anybody familiar with these kind of problems and a solution ?

Shift+L sets the loop range and L turns it on. Any chance you are bumping these hot keys?
 
Looping being on is indicated by a yellow bar at the time of the ruler for the timeline.

No I am sure that was not the case. I call it looping as it sounds like a two note loop but it is a Sonar crash. But the next time it happens I will pay extra attention to the loop signs, thanks.