I'm having an issue with my 2011 Mini getting totally froze when I disconnect my VPN. I'm running Lion. It doesn't happen every time, just very randomly. It freezes so bad I'm forced to hold down the power button and have it restart. I can't force quit or get any response at all. The menu bar status scrolls "disconnecting" forever. Needless to say anything I was working on that didn't save is lost. Any idea whats causing this?