iMac won't wake from sleep


macrumors 6502
Original poster
Feb 14, 2005
B'ham Uk
Hey, having some trouble with my iMac (the version right before the intel iMacs came out. further info can be provided if needed).

Running all the latest software updates etc.

When I put the iMac to sleep, it goes off as normal. With the usual white light. However, when coming to wake the iMac it won't respond to the keyboard or mouse. I have to shut it down at the power button, and then turn it back on. This is gettin very annoying - its been going on for a while now and I just got round to trying to sort it out!

Any help would be great, thanks.



macrumors 65816
Dec 5, 2005
Your probebly useing a bluetooth mouse and keyboard, you need to check teh little box in your bluetooth options that says something along teh line of "allow bluetooth devices to wake up this computer". I had the same problem with my iMac.


macrumors newbie
Feb 9, 2009
Recently, my iMac won't wake up, I have to shut it down to make it come alive.

Recently, my iMac won't wake up, I have to shut it down to make it come alive.
Anyone know why this is happening and how to fix it.

jive turkey

macrumors 6502
Mar 15, 2008
This happens on my Pro desktop every once in a while. I am not using anything bluetooth or wireless on this machine. I think it has something to do with a corruption in the saved memory. I would have this problem EVERY time the Mac went to sleep until someone here suggested using Grand Perspective to search my drive. I found a 4GB chunk of saved memory that I deleted, and the problems now happen only occasionally.

I have not taken formal notes, but judging off of memory (that is, when I am actually paying attention), the "won't wake from sleep" issues usually follow after I am away from my computer for 10 minutes so, then come back. I am guessing that I catch the computer as it is preparing for sleep and saving the memory, and when I interrupt it something goes wrong. The next time she goes to sleep it won't wake up.

If you are having problems every time, get Grand Perspective (it's free) and see if you have some memory saved. I don't remember what the saved memory block is called, but I am sure someone reading this thread can help you. I seem to remember it was pretty obvious.


macrumors newbie
Feb 12, 2009
If your iMac does not wake from sleep mode...

... I've been fortunate to follow advice from some forum or other (possibly this one, but I think not) to "zap the PRAM" or reset the PRAM by holding down Command-Option-P-R until you hear a second chime.

Worked for me; I have a new aluminum-frame iMac and am running OS X 10.5.8.


macrumors 6502a
Sep 18, 2006
Alicante, SPAIN
Yeah that's what has been happening to me too. Hmmmm:confused:
Same here too on my parents iMac. It only happens occasionally, although more recently about 3-4 times a month, but each time they have to hold down the power button to power off and then power on again.

Its a bit of a pain in the arse because I do not know what is causing the problem and therefore cannot tell them.


macrumors 6502
Mar 4, 2008
I'm getting this too, since the last security update I think

2.4 Alu iMac using 10.5.6. Bluetooth Logitech mouse & wired Apple keyboard

Am currently Safe Boot Mode to see if it reoccurs

May try resetting the PRAM

Quick hardware test came up with one issue, extended test returned with nothing :confused:


macrumors regular
Aug 5, 2006
This too has been happening to me. I believe it started about a month ago. I have the Aluminum with 10.5.6.

I will try zapping the PRAM to see if that helps. Did that work for others?


macrumors member
May 4, 2007
Airport Express may be the problem!

I know this thread is old but I thought I'd share my experience.
I had my Airport Express card switched ON and was creating a wireless network. When I shut down or put my iMac to sleep it would become unresponsive.
So what I did was switch OFF the Airport (wireless network) before shutting down or putting iMac to sleep which solved the problem.
I hope this helps everyone.:)


macrumors 6502
Jan 24, 2010
Same problem

Sorry for bumping an old thread, but I have had my Apple wireless keyboard for six months or so now, and have been a happy camper with it, but just recently I had to replace the depleted batteries, and in doing so, I also replace my Magic Trackpad batteries too.

Now upon switching on both devices, I have noticed whenever my MacBook goes to sleep, I simply cannot use either bluetooth devices to wake it up.

I thought ok, must me a setting that had reverted back to default. Sadly when I found the setting I needed, its greyed out, and not allowing me to tick it. See screen below.

Has anyone else experienced this, and if so, how to get this option to allow bluetooth devices to wake up my sleeping MBP?

Thanks in advance to anyone who can help, as this is driving me nuts.


macrumors 6502
Jan 24, 2010
Ok, I found the issue. I noticed that the option to turn my bluetooth off was missing, so shut MBP down for a few minutes, and fired it back up, then I found both the option to switch bluetooth off, and the option to set BT devices to wake Mac up available again.

Just thought I would share in case anyone else faces this odd issue.