So, pretty much out of nowhere, my trusty old Macbook Pro started shutting down on me. Frequently. Sometimes several times within an hour. Sometimes it would go for hours on end with no trouble. This continued for a couple months of me trying different things: not putting the machine to sleep between uses, switching browsers, uninstalling extensions, I really had no idea when it all started. I seriously considered having the logic board replaced, which would not have been cheap. After hours of combing and reading the message boards and all the info I could find about kernel panics, I finally identified the culprit. Sophos Anti-Virus.