Argh. This has happened often enough lately to get me to consider bringing in my macbook pro for service before the 1 year guarantee runs out.
Apparently plenty of other people have had sleep issues with MB Pros, either not going to sleep or not waking from sleep. What’s really annoying about it not waking up is that in the end you have to do a hard reboot, which means you lose whatever you were working on when you decided to give the machine a nap, a *big* interruption in workflow when you return from the kitchen.
First thing I’ve decided to try (before running down to the Apple Service folks) is to uncheck “Put the hard disk to sleep when possible” under the Energy Saver System Preferences. I did this for both battery and power adapter settings (usually I have the mb pro plugged in).
Others have decided to disable Deep Sleep mode using the Terminal (thank you Mac OSX Hints). I think I’ll try that too. Not a scientific approach, alas, but this problem is irritating enough that I’ll try 2 things at once – if it’s OK afterwards, I’ll forfait finding out which worked/didn’t work.
I also decided to recover the hard disk space that deep sleep uses.
Since this problem happens occasionally (haven’t reproduced it, don’t know if it’s reproducable), time will tell if these changes work.