2011 27 inch iMac will boot from off condition every single time and runs fine once booted. But if I attempt to restart it, it boots to a single chime with a black screen. I can hold the power button down to turn it off and then power it up again, but it will not warm restart. Any ideas where to start diagnosing this issue?
Thanks
1. The worst thing that you can do is shutdown or restart your Mac when it is hot. Think about it, everything is really really hot and you click shutdown or restart which stops the cooling fans. It really is best to stop all activity and let the display sleep for a while to let things cool off before shutting down.
2. When was the last time you cleaned the bottom grill work on your iMac to make sure that it is cooling properly...? I shutdown a couple of times a year and seriously vacuum out the dust build up on bottom grill on my iMac's.
3. You also might consider only sleeping your iMac 24-7, instead of shutting it down.
If you are having other problems like Kernel Panics that are forcing you to restart or black-outs from possible over-heating, then please explain in more detail what is happening.
This iMac gets shutdown after every use, because it's in a church sanctuary and only used once a week. And while I understand what you are saying, if I shut it down when it is hot, it still boots perfectly fine as long as I power it down completely and not do a restart. So I am not sure that heat is the issue. I will definitely clean out the bottom grill and make sure it has good air flow. It can't be left on 24-7 because it's on an outlet that also has a sound board attached and everything is shut down on Sunday after services. I am not having any kernel panics or black-outs, the computer runs fine, no issues. The only reason I noticed this was because I was updating and it said it would restart to finish installing, only it never restarted. That's when I investigated and realized it won't start on a restart but only will on a complete shut down. Thanks!
Hi, 3 checks to try:
- Suggest you try a NVRAM Reset : http://support.apple.com/kb/ht1379 and test a warm reboot.
- if the issue persists, try a : Intel-based Macs: Resetting the System Management Controller (SMC) and test a warm reboot.
- Check Apple menu -> System Preferences -> Startup Disk that the correct disk is selected and click the Restart button to warm reboot
See how you go
Aha, OK!
You would be surprised how much dust can acumulate on the bottom, even if it is only used several days a week.
I would shutdown and disconnect everything from it, lay it face down on a soft cloth and give it a really good vacuuming out. Doing it that way will also reset the System Management Controller, which should also help to resolve any Restart, Startup and Shutdown problems.
see > Intel-based Macs: Resetting the System Management Controller (SMC)
I have reset the PRAM, but no joy. Will reset SMC tomorrow after church services. Thanks!
iMac won't warm restart-cold boots fine
