How do I know which process is causing my computer to hang?

Solution 1:

If you can't launch or switch programs (I find Spotlight is a good way to do this if everything else is hanging, just hit ⌘Space, but it may not work in your case), you could enable SSH access ahead of time, and then use another device to log in and check what's hogging your CPU.

Open Sharing Preferences and enable Remote Login. Then you can connect via SSH from another Mac, PC or iOS device (you'll need PuTTY on Windows, and one of various SSH clients available on iOS). Once you're logged in, type top -o cpu to get an updating display of processes ranked by CPU usage. That should give you a hint as to what's causing the problems.

Solution 2:

vtd is not well documented on OS X. I did find one post on InsanelyMac (hackintosh forum) suggesting that it has to do with Intel's VT-d technology, which allows virtual machines to access hardware more efficiently.

By the console message, it looks like the problem is coming from a kernel extension. I would suggest running the OS X 10.8.2 combo update, which hopefully will overwrite any offending kexts with good copies.

If that doesn't fix it, your next best option is to file a bug report with Apple since not a lot of people share this issue. They take awhile to respond, but things will eventually be fixed.