This is probably caused by one of the plug-ins that you're using. If any of the plug-ins that are loaded as part of your project crash, they take all of Sonar with them. When does it happen? Have you just added a synth or effect to a project? Have you just opened a project? Bryan On Jan 24, 2012, at 11:30 AM, Sergio Felicano wrote: Hi everyone, I am having an issue with sonar 8.5. I keep getting an run time error message and then it freezes up the computer to the point that I have to reboot the computer. This is happening quite often, does anybody have a solution for this particular problem? Bolo