I'm encountering this problem as well on my 27 inch core i7 imac. When my iMac goes to sleep I cannot wake it up and am forced to hold the power button for about 10 seconds in order to power it down before powering it back up. I am going to disable the sleep feature until a fix is found.
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27" iMac won't wake from sleep
- Thread starter jcphoenix
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hmmm..turns out my problem is different. I assumed my computer was going to sleep and could not wake because for the last two mornings I have found my computer unresponsive. And a simple press of the power button would not start it up. I had to hold down the power button for 10 seconds to force it to power down before I could power it up. Anyway, I checked my sleep settings and I already had it set to never sleep. The screen will sleep and so will the drive.
I got my iMac a little while ago (27") and I have been kinda used to the problem of my Macs never waking up properly. The first time it happened on this machine it appeared to be the magic mouse losing bluetooth connection. I changed to a USB mouse and it worked fine for several days. However today it happened again and the mouse was working (the laser was on) however the computer wouldn't wake up. I tried to click the keyboards volume buttons to see if the computer was on and working and only the screen was off, but the sound buttons had no effect. I had to restart.
I did a clean install of the system, and then migrated key files manually from my external to this machine. I also have an external HD plugged in, as well as a Gigaware USB hub. I haven't tried unplugging these things yet.
I did a clean install of the system, and then migrated key files manually from my external to this machine. I also have an external HD plugged in, as well as a Gigaware USB hub. I haven't tried unplugging these things yet.
It has been two days since I plugged my new 27" iMac directly into the wall socket and no spontaneous shutdowns or issues waking up from sleep. Compare this with at least one or two shutdowns when connected to my battery backup / surge protector and I'm guessing I've got a faulty battery backup / surge protector. I'm going to go out and pick up a new one.
Others with the same issue might want to try the same test. Perhaps the power supplies in these new 27" iMacs are very sensitive to variations in the current being supplied to them.
SMC reset, + Energy Saver settings, worked for me.
I have had this wake from sleep issue with my late 2009 27' quad core since it arrived. The problem has been random and hard to pin down.
After reading everything here I decided to try the SMC reset ( unplug computer, hold start button in for more than five seconds, plug in and start).
In Energy Saver settings under System preferences, I also set the "computer sleep" setting to "never", unselected the "Put hard disk to sleep when possible", and unselected "Allow power button to put the computer to sleep"
I did this 5 days ago, and so far have no problems with waking the computer with mouse or keyboard.
I still allow the display to sleep after 10 minutes
As you might expect, with the computer now never sleeping, the display wakes up nice and fast. Of course this is not the most energy efficient solution, but I was not enjoying having to force the computer to shut down on a regular basis.
I would recommend trying the SMC reset before any other fix, its easy, fast and non destructive.
I have had this wake from sleep issue with my late 2009 27' quad core since it arrived. The problem has been random and hard to pin down.
After reading everything here I decided to try the SMC reset ( unplug computer, hold start button in for more than five seconds, plug in and start).
In Energy Saver settings under System preferences, I also set the "computer sleep" setting to "never", unselected the "Put hard disk to sleep when possible", and unselected "Allow power button to put the computer to sleep"
I did this 5 days ago, and so far have no problems with waking the computer with mouse or keyboard.
I still allow the display to sleep after 10 minutes
As you might expect, with the computer now never sleeping, the display wakes up nice and fast. Of course this is not the most energy efficient solution, but I was not enjoying having to force the computer to shut down on a regular basis.
I would recommend trying the SMC reset before any other fix, its easy, fast and non destructive.
This is interesting. I noticed my problem starting correlated with me adding an uninterruptable power supply to my iMac...
...
Hmm...
You would THINK that an UPS would give it perfect, flat, unvaried voltage. What a bummer. I bought one well overrated for my needs, I didn't expect to have problems. If this IS the problem, I'll be pretty upset.
-Allen
OK Unfortunately I rebooted and plugged straight into the wall and had the exact same problem, even WORSE actually (!!)
So this wasn't the issue for me. Computer is now with an authorized apple repair shop to tear it apart, and make it stronger.
It seems like that the exact issue I have.
If I'm testing it doing a quick sleep cycle I can put (my brand new) iMac to sleep manually from the finder or using short cuts and it will power up just fine.
If I do the same before I go to sleep, the iMac won't wake up in the morning.
I had a similar issue with my mid 2010 core i5 as well.
However, in my case, the display would refuse to turn back on, even though the Mac was still running - and I tried it all, keys and mouse movement, etc. I am using the wired Apple Keyboard and MX Revolution mouse.
I solved it by reinstalling Snow Leopard using the 10.6.4 disk I got with the machine (instead of a retail 10.6.3 disk I had lying around), and since then haven't seen the issue reoccur.
However, in my case, the display would refuse to turn back on, even though the Mac was still running - and I tried it all, keys and mouse movement, etc. I am using the wired Apple Keyboard and MX Revolution mouse.
I solved it by reinstalling Snow Leopard using the 10.6.4 disk I got with the machine (instead of a retail 10.6.3 disk I had lying around), and since then haven't seen the issue reoccur.
SMC reset
I had the same problem and I did SMC reset and the problems gone. My IMac 27 I5 is working fine, I am using a Targus usb hub, seagate firewire drive, bamboo pen and touch and everything is fine.
I suspect that the problem start when the ambient temperature raise a lot last week.
see at: http://support.apple.com/kb/HT3964?viewlocale=en_US
Bad News!
The problem return 24 hours after SMC reset!
I had the same problem and I did SMC reset and the problems gone. My IMac 27 I5 is working fine, I am using a Targus usb hub, seagate firewire drive, bamboo pen and touch and everything is fine.
I suspect that the problem start when the ambient temperature raise a lot last week.
see at: http://support.apple.com/kb/HT3964?viewlocale=en_US
Bad News!
The problem return 24 hours after SMC reset!
I also saw that behavior that the iMac didn't woke up after sleep. I got my iMac in mid 2010 (27", i7, 2.9) and installed SL fresh from disk. The new iMac was replacing a McMini. The Mini never had that trouble. Connected is a cable-keyboard and MagicMouse. 
I read here that some USB components might be a problem so I looked down the chain of USB cables. First connected to my iMac is a ACD 24" screen; on that one I had only a DisplayLink adapter to connect occasionally a third monitor.
First I removed all those and disconnected the ACD and DisplayLink adaptor.
And voila: the iMac woke up.
The downside was that the ACD 24" was kind of required due to my desk layout to connect my iPhone/iPad. The standard cable are too short.
So I connected the ACD back (but still left the DisplayLink adaptor away).
And one more voila: still the iMac wake up.
So what does it mean: might be linked to connected hardware as mentioned before here many times.
I know its too early to draw a conclusion but I wanted to share it ... maybe someone can build on it as its really disturbing to force a restart each day.
I read here that some USB components might be a problem so I looked down the chain of USB cables. First connected to my iMac is a ACD 24" screen; on that one I had only a DisplayLink adapter to connect occasionally a third monitor.
First I removed all those and disconnected the ACD and DisplayLink adaptor.
And voila: the iMac woke up.
The downside was that the ACD 24" was kind of required due to my desk layout to connect my iPhone/iPad. The standard cable are too short.
So I connected the ACD back (but still left the DisplayLink adaptor away).
And one more voila: still the iMac wake up.
So what does it mean: might be linked to connected hardware as mentioned before here many times.
I know its too early to draw a conclusion but I wanted to share it ... maybe someone can build on it as its really disturbing to force a restart each day.
Not awake? Not asleep!
My Mac is on a Watt meter, so I can see if it really sleeps.
The times it is not able to wake up, it actually was not able to get asleep.
After pressing the button for sleep, the display turns of pretty soon. But the Mac still runs for some time till it gets to sleep. In this time one can only slightly hear the fans running.
Usually this state holds just for a couple of seconds. But sometimes it also extends to some minutes, and once in a while it even freezes in that state.
Don't know what it does in that state. But it seems that the "don't awake" problem is actually a "don't sleep" problem.
I also noticed that when I press keys during the doze off phase, I won't be able to wake it up with my BT-kb anymore, even if it finally fall asleep. I suspect the same with the mouse and the power button. If you pressed them during the doze off phase, you might stuck even if the Mac finally came to sleep and won't be able to reanimate it without a total shut down.
Cheers,
Nobody
My Mac is on a Watt meter, so I can see if it really sleeps.
The times it is not able to wake up, it actually was not able to get asleep.
After pressing the button for sleep, the display turns of pretty soon. But the Mac still runs for some time till it gets to sleep. In this time one can only slightly hear the fans running.
Usually this state holds just for a couple of seconds. But sometimes it also extends to some minutes, and once in a while it even freezes in that state.
Don't know what it does in that state. But it seems that the "don't awake" problem is actually a "don't sleep" problem.
I also noticed that when I press keys during the doze off phase, I won't be able to wake it up with my BT-kb anymore, even if it finally fall asleep. I suspect the same with the mouse and the power button. If you pressed them during the doze off phase, you might stuck even if the Mac finally came to sleep and won't be able to reanimate it without a total shut down.
Cheers,
Nobody
I've now had this problem 3 times in the past week.
Screen won't wake up. Computer is fine, when I plug in an iPad or iPhone it syncs, so I know the iMac is awake. Normally this would cause the login window to display. Had to pull the plug on it 3 times. Strangely, it never tried to repair disk after pulling the plug. Must be a software issue right? It's an i7 iMac bought around june
Screen won't wake up. Computer is fine, when I plug in an iPad or iPhone it syncs, so I know the iMac is awake. Normally this would cause the login window to display. Had to pull the plug on it 3 times. Strangely, it never tried to repair disk after pulling the plug. Must be a software issue right? It's an i7 iMac bought around june
Issue Solved - Following Up on Original Post
All: wanted to let you all know that this turned out to be a hardware issue that Apple addressed via a Genius Bar appt. It was a while ago so I can't recall what they replaced, but it's been working fine since. My advice - take your computer to a licensed Apple repair shop and have them diagnose the issue. Good luck!!
All: wanted to let you all know that this turned out to be a hardware issue that Apple addressed via a Genius Bar appt. It was a while ago so I can't recall what they replaced, but it's been working fine since. My advice - take your computer to a licensed Apple repair shop and have them diagnose the issue. Good luck!!
USB as problem found ?
I have the same issue. Yesterday it came back from repair. But the problem still seems not be be solved.
When the sleep timer expired, the iMac froze every second or third try.
New investigations:
I disconnected all USB devices, rebooted again. After 10 sleep/wake cylces I was curious why my iMac is still alive.
I plugged in my iPhone4 and the with the then upcoming sleep clycle, the behavior was as always. The iMac freezes immediately after going to sleep.
As mentioned before. This is not a real sleep. Fans are still working, display remains dark, network connection lost. Only a hard reboot can bring the iMac back to work.
I will have an Genuis Bar appointment the following week. May be someone can reproduce this "solution".
Best wishes,
Peter
I have the same issue. Yesterday it came back from repair. But the problem still seems not be be solved.
When the sleep timer expired, the iMac froze every second or third try.
New investigations:
I disconnected all USB devices, rebooted again. After 10 sleep/wake cylces I was curious why my iMac is still alive.
I plugged in my iPhone4 and the with the then upcoming sleep clycle, the behavior was as always. The iMac freezes immediately after going to sleep.
As mentioned before. This is not a real sleep. Fans are still working, display remains dark, network connection lost. Only a hard reboot can bring the iMac back to work.
I will have an Genuis Bar appointment the following week. May be someone can reproduce this "solution".
Best wishes,
Peter
I had this same problem with my 2007 iMac and it had been ongoing for over a year. Before my 3 year Apple Care was up I decided to take it in to be looked at, this was back in August. After over 3 months of been in-and-out of repair (4 times in total) and several major components been replace (Logic Boards, Super Drives, HDDs, OS System etc etc costing over £850 - Luckly I was under Apple Care), I took my iMac back to the Apple store again today with the same problem expecting for it to go in for repair but this time they have told me that the machine is now classed as a write off and I will be getting a brand new shiny 2010 iMac delivered in the next two weeks. Don't give up guys keep taking them back and getting them looked at they will either fix it or replace it!
I can't say this enough - Get Apple Care - Its worth it!!!
/Rookie
I can't say this enough - Get Apple Care - Its worth it!!!
/Rookie
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No mike sounds
My 21.5 imac I think, is great and performs very well (so far). I even use XP on it without problems, that is until I want to use the Sound recording. Sounds generally are very good but when using Sound recording on XP portion it says not enough memory for the task, close some programs when none actually are being used. Strange.
Any help out there would be much appreciated
My 21.5 imac I think, is great and performs very well (so far). I even use XP on it without problems, that is until I want to use the Sound recording. Sounds generally are very good but when using Sound recording on XP portion it says not enough memory for the task, close some programs when none actually are being used. Strange.
Any help out there would be much appreciated
I am having a similar sleep problem with my 21.5 iMac, although I think it's only the screen that is sleeping. The other problem which could be related is a frquent blue screen freeze when fast switching between accounts. This also requires a forced restart.
Any chance you could return to the Apple Store, ask them for the repair history and then list here what parts they replaced? Some Geniuses have no idea, some just replace various bits each time you return, and it seems a small handful know what is going on and have found a solution. We need the latter detailed here...
essentially brand-new 21" i3 iMac, same problem
Nothing at all special about the machine--completely stock base 21" model. Took it home, migrated data from old iMac via Firewire. Everything good for about a week. Now have had a few episodes where the machine (seemingly) won't awake from sleep state, regardless of mouse use, key presses, expletives, threats, bribes, and offers of arbitration. Have had to power down with ten-second power button press, then restart. All seems okay after that, until it happens the next time. Note, however, that this problem does NOT occur with each episode of the machine going to sleep. (Or trying to; whichever.)
In reading through a fair number of the posts above, I'd like to offer a few comments, ideas, what have you.
Firstly, it's almost certainly NOT related to variable power supply issues. Forum participants report it happening with surge protection, without, and with UPS. Possible, I suppose, that Apple procured a large batch of faulty power supplies, and the problem is intrinsic to those, but that explanation fails to account for why the problem has been present off/on for quite some time, with various types of machines. (At least one forum member reports it happening with a MBP, though certainly the preponderance (at least) seem to be iMacs of relatively recent vintage--though not all even with the last year or so.
Other hardware issues as possibilities are limited by those factors that are common to all of us having problems. This is where setups like mine may help reduce the list of suspects--all that we have attached to our machine is a power cable. No other USB devices, no printer, nothing. We do have an Airport Extreme network setup--have had for quite some time, and it has had no recent changes. The power cable is plugged into a surge protector, but see above re: that.
Already, we're starting to look at a software glitch as the likely culprit. Details of setups are going to be important here, as the problem could perhaps be related to interactions of screen saver and sleep, specific settings for each or either, perhaps even how any changes were made. How many of us made changes to the factory default settings of sleep mode for either display or machine? I've made a slight change regarding timing of things, but nothing else. One discouraging bit about the possibility of software glitch is that OS X reinstall doesn't (at least reliably) fix the problem.
But there are lots of possibilities in that arena (the software glitch arena--it's a big one--they featured it in a Russell Crowe movie a while back). Could it have to do with what program(s) are still running when the machine goes to sleep? I, for instance, occasionally leave Firefox running, and Mail sometimes. My wife likes Safari, but I happen to know it was NOT running during the last "won't wake" event for us. Not sure about Firefox, others, for us.
And how about software installation? Is it possible that there's an installation/setup step for something that, when done "just wrong", results in this? Are all the sufferers people who moved from old Macs and migrated data/settings? Could that be related?
If anyone has solved this--not found a work-around, but rather solved it, it'd be great to hear about it. I'm not looking forward to spending hours with support people trying to work this out.
Nothing at all special about the machine--completely stock base 21" model. Took it home, migrated data from old iMac via Firewire. Everything good for about a week. Now have had a few episodes where the machine (seemingly) won't awake from sleep state, regardless of mouse use, key presses, expletives, threats, bribes, and offers of arbitration. Have had to power down with ten-second power button press, then restart. All seems okay after that, until it happens the next time. Note, however, that this problem does NOT occur with each episode of the machine going to sleep. (Or trying to; whichever.)
In reading through a fair number of the posts above, I'd like to offer a few comments, ideas, what have you.
Firstly, it's almost certainly NOT related to variable power supply issues. Forum participants report it happening with surge protection, without, and with UPS. Possible, I suppose, that Apple procured a large batch of faulty power supplies, and the problem is intrinsic to those, but that explanation fails to account for why the problem has been present off/on for quite some time, with various types of machines. (At least one forum member reports it happening with a MBP, though certainly the preponderance (at least) seem to be iMacs of relatively recent vintage--though not all even with the last year or so.
Other hardware issues as possibilities are limited by those factors that are common to all of us having problems. This is where setups like mine may help reduce the list of suspects--all that we have attached to our machine is a power cable. No other USB devices, no printer, nothing. We do have an Airport Extreme network setup--have had for quite some time, and it has had no recent changes. The power cable is plugged into a surge protector, but see above re: that.
Already, we're starting to look at a software glitch as the likely culprit. Details of setups are going to be important here, as the problem could perhaps be related to interactions of screen saver and sleep, specific settings for each or either, perhaps even how any changes were made. How many of us made changes to the factory default settings of sleep mode for either display or machine? I've made a slight change regarding timing of things, but nothing else. One discouraging bit about the possibility of software glitch is that OS X reinstall doesn't (at least reliably) fix the problem.
But there are lots of possibilities in that arena (the software glitch arena--it's a big one--they featured it in a Russell Crowe movie a while back). Could it have to do with what program(s) are still running when the machine goes to sleep? I, for instance, occasionally leave Firefox running, and Mail sometimes. My wife likes Safari, but I happen to know it was NOT running during the last "won't wake" event for us. Not sure about Firefox, others, for us.
And how about software installation? Is it possible that there's an installation/setup step for something that, when done "just wrong", results in this? Are all the sufferers people who moved from old Macs and migrated data/settings? Could that be related?
If anyone has solved this--not found a work-around, but rather solved it, it'd be great to hear about it. I'm not looking forward to spending hours with support people trying to work this out.