That's unusual; I got a 12" fairly recently, and I believe it was set to sleep, eventually. Perhaps something was running that cancelled sleep? What exactly did the logs say about sleep? As far as temperature goes, 125 degrees is reasonable; that's the temperature inside the CPU. The temperature drops pretty quickly as you get further from the CPU (eg out to the case). The fan will kick in at an appropriate temperature to keep the CPU and GPU cool enough, though this temperature varies by model, and also somewhat by individual computer. Mine (17" 1 GHz) turns on the fan at 140 degrees F, and off at 130. There are separate temperature thresholds for the GPU, but I've never bothered to figure them out. Furthermore, even if your fan weren't working, there is additional protection built in to every recent Apple portable; they go into reduced processor speed at a certain temperature (WELL over the temperature that the fan kicks in at - I have never seen a PowerBook get anywhere close to that temperature, and I've worked with hundreds if not thousands of PowerBooks), and then is forced into sleep a few degrees higher. The only way for it to get this hot, of course, would be for the fan (or fans) to fail completely, and then for it to run some extremely processor-intensive tasks for a while. Even then, I'm not sure it would be able to get all the way up to that temperature without some component producing more heat than it should be. But just so you know, the protection is there, just in case. John Griffin <jwegriffin at mac.com> writes: > As I just found out, for some reason Apple in its infinite wisdom set > the > Energy control so that the Powerbooks will never go to sleep either on > the > battery or on the adaptor. > > I just discovered this today when I walked into my office that my > computer > had been on all night and the display showed the log-in window. The > temperature was at 125=B0 (but I could not hear any fans > going...hmmm!) The > System logs said that it rebooted (Macaroni's does this after running > Cron > scripts) at 3:00 am and tried to go to sleep on numerous occasions, > but that > sleep was not enabled on my machine.