I have a Mac mini that I use as a home file server, running Snow Leopard. Occasionally, the computer locks up, but since it’s headless (or running without a display attached), I don’t always realize it. Do you know of any software or web services that could run in the background, and if the machine freezes, alert me via email or text?
Reports are streaming in that OS X Lion is freezing up for some users. Although reports indicate problems at the login screen or after waking up the machine from sleep, many of the issues seem to occur around playing video clips in iLife apps.
For many users, it appears a hard reset fixes the problem. One user experienced multiple frozen screens when using iMovie, only to have the issue resolved after repairing permissions with Disk Utility.