Last night I was chatting with my friend Josh about his new puppy when my computer suddenly went to sleep. At first I thought there was a power failure, but then I realized that my laptop has a battery, and then I noticed the sleep light was pulsing, so I pressed a key to wake it up.
This morning it happened again. And then again. It seemed to become more and more frequent until I restarted my computer, and then it was fine. Until it went to sleep again. And then it wouldn’t wake up. So I tried to do a restart with ctl-apple-power, and that didn't work. So I tried to shut it down by holding down the power button, and that didn’t work. So I tried to shut it down by removing the power cord and the battery.
That didn't even work. The sleep light continued to pulse despite the lack of any visible power source. I’m sure there’s a reserve battery in there somewhere, but I didn’t expect it to power the sleep pulse light. Eventually it died and I replaced the battery and the power cord and restarted and everything was fine. Until it happened again.
Quick learner that I am, I started to realize this problem wasn’t going to go away. I decided to try to figure out what was going on before tomorrow when the help desk guys at work could look at it, in case it was no longer running tomorrow. Somewhere in there I had run disk utility and found no apparent problems with the hard disk, so I figured at worst the hard disk would need to be moved to a different machine. No data loss, no problem. But you never know.
So I went searching online and found some information suggesting I should reset my Power Management Unit. So I followed the instructions from Apple, or at least I think I did. The process doesn’t include any indication of whether or not anything is actually happening. I might as well have been waving a crystal over my PowerBook for all I could tell I was doing.
No spontaneous insomnia yet in the time it took me to type this. Time to burn some backup CDs. Apparently it’s Backup Sunday anyway.
Update: about an hour later, it grew sleepy again. After reading more, I found a suggestion to delete
/Library/Preferences/SystemConfiguration/[SomethingToDoWithPowerManagement].plist. I’d tell you the actual file name, but it hasn’t reappeared yet. No sleepiness since, so I guess that’s okay. I hope.