MacBook Pro Freezing

Suggestions:

• Run Mac in recovery mode (keep holding ⌘ cmd + R on startup), then try to Repair Disk and Repair Disk Permissions using Disk Utility.

• As suggested in Mountain Lion Screen Freeze thread, try OnyX software which allows and to verify the startup disk and the structure of its system files, etc.

• Run dmesg and check /var/log/system.log for more detailed errors.

• Run Console app to check crash logs including backtraces if any.

• Run newproc.d or iofile.d dtrace scripts to find anything suspicious (e.g. sudo newproc.d)

^{Related:
Apple.SE: Mountain Lion Screen Freeze
Apple Discussions: Mountain Lion Screen Freeze (over 177 replies)}