iMac won't wake up from sleep using keyboard or mouse

So sorry, one important correction for this post:

Step 4 should read:
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4. Set both the 'Computer sleep' & 'Display sleep' times to MORE than the 'Start screen saver' time amount. This will ensure that your screen saver always starts before the iMac goes to sleep.
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not "'less' than the 'Start screen saver' time amount."

It has to be 'MORE' for this process to work.

SIMPLE 2-STEP SOLUTION that works for my iMac (2007 model Intel core duo) when it gets stuck in sleep mode where the screen is black and the pulsating light on the front lower right corner of the machine stops pulsating and gets stuck lit.

Simply, (step 1) press and release the power button on the back of the unit with your left hand if you are facing the front of the desktop machine's display. Note: DO NOT HOLD the power button as that will force a shut down of the machine. By doing so, the machine will go to power conservation mode or perhaps sleep mode (again); You will actually hear a subtle sound change like the internal fan actually stops. Then (step 2) press and release (DO NOT HOLD) the power button again. This will wake up the machine and you will see your working screen-saver image(s) appear on your display screen. Now you should be good to go 🙂

Andrew K

Message was edited by: Winged Hussar

I have this problem too with a new iMac and also discovered same solution as Andrew K. Only thing I can add is that I have checked the "Allow power button to put computer to sleep" in the Energy Saver system preference panel.

I have long suspected this has something to do with devices: either firewire or usb 2.0, maybe even having extra monitor. At any rate, the machine is not really asleep in this state. You can push the "play" key on your keyboard and iTunes will play! It's more like the graphics display just won't come on. By setting the preferences, you can basically put the machine to sleep with the power button (you'll hear the fan shut off), then wake it up properly by pushing the button again. Annoying, but no work lost.

Richard

My brand-new 21" iMac (Intel) is doing the same thing. Won't wake up from sleep, even when I (just for fun) inserted a CD into the drive to 'stimulate' it a bit. Workaround seems to be like others describe; press the power button briefly, release, then tap a key on the keyboard or move the mouse.
I had similar problems with an older G5 iMac the day that I added an external HD for Time Machine. That problem went away when I moved the HD connection from Firewire 400 port to the USB 2.0 connection.
The new iMac also has an external HD for Time Machine, connected via Firewire 800. I haven't experimented with that yet. Does anyone see a commonality with this experience?

And I'm another one with this problem. Brand-new 27" i5. First two days were OK, and then (after the latest security update) it would no longer wake from sleep with the keyboard or mouse. I have found the power button trick described above works OK, but I would love for Apple to provide a real fix for this problem.
Contrary to the posting above, I found the relative timing of Screen Saver and Energy Saver timing has no effect.
It does seem the cause is that the machine cannot really go to sleep from the Energy Saver settings ... only the power button really puts it to sleep.

I have had my iMac 21.5" for around 7 months. Within the last week, my wife and I discovered that after the iMac goes to sleep, the wireless keyboard and the wireless mouse will not wake up our computer. Even pressing the power button will not wake it up; all we could do is restart the computer.

We only have a printer, ISP modem, and an external Lacie (800 fireport) attached to our iMac.

I called Apple tech support (we have the 3 year care plan) and was asked if I had downloaded any updates recently. Well, after the amount of problems I had with the incompatibility (when I downloaded Safari a while back) with my modem and the latest downloaded Safari, I no longer use Automatic Updates. However, after several days of ignoring updates, I finally downloaded whatever updates were recommended by Apple, since I went to their site and had it search for any updates I did not have.

The Apple Tech fellow told me, as far as putting our iMac to sleep, to do what was suggested above. Namely, press the power button to put the computer to sleep and press it to wake it up. He also suggested instead of our using a wireless keyboard and mouse, we could use USB ones. Hmmmmmmm....now that seems a bit odd, since Apple seems to think the wireless gadgets are quite nice -- and so did we.

And when I commented that it is more than a bit of a nuisance that I can't trust Apple to know if updates are good for my iMac or not, he suggested that first I read the forums on this site to see if others are having problems with the updates.

We like our iMac when things work, which they usually do. But we have had quite a few more annoying problems in these first 7 months than we thought we would.

I've noticed, too, that the top of our 21.5" unit is getting quite warm (not hot); I don't remember it being that warm before; but according to the threads I have read on this site, it is normal for the iMacs to be "hot" at the top of the units. However, this "hot" aspect seemed to surprise the tech person who helped me.

I will say that Apple Care Tech people have been friendly and very willing to stay on the line. I also appreciate all the help you people give on these forums.

I read through this whole thread to find an answer - seems like this is not one problem but several.

My new 2010 iMac 27-inch 2.93 i7 had already been replaced once (wouldn't start up, and had a burning smell from bottom RH corner), but the wake from sleep issue continued with the replacement. As I had brought across a 2TB disk from a failed G5 tower, it seemed the possible causes were endless.

Thanks to the suggestions in this thread, I narrowed it down to a 7-port powered USB hub. When that's disconnected, the problem disappeared.

I'd be grateful if anyone could suggest a good brand of 7-port hub which is not giving problems in a similar situation.

I had the exact same "not waking up from sleep" issue with the exact same iMac model. I noticed that after replacing the batteries in the wireless mouse, the problem stopped. Then, when the batteries in the mouse began to die again, the problem came back. I decided to see what would happen if I only used a USB mouse, and I'm glad to say that it has been a week since the last "not waking from sleep" incident. Perhaps the problem is caused by a disruption in the bluetooth signal when the battery power gets too low?

It's really frustrating to see that many people have the same issue (look in Google and on Macrumors forums) but no one found a stable and real solution...

I tried to:

reset SMC
reset PRAM
unplug my firewire HD
plug directly my iMac in the wall socket
play with the energy saver settings as well as screen saver
cool down the room
plug an external monitor and unplug it
switch off my magic mouse
put my iMac to sleep with the remote control and wake it up with it
put my iMac to sleep from the power button and wake it up with it
put my iMac to sleep from the menu and wake it up from the keyboard
every combinations of these sleeping methods !
change the batteries of the magic mouse
reactivate only by pressing a key on my USB keyboard

No success !!! And what is more worrying is that Apple Care have no solution...

Will a reinstall solve this ? Not even sure... 😟

Please Apple, DO SOMETHING !

I agree that it seems like many different things can cause this problem. Mine, for example, is now solved. I updated with a patch for the OS (when Software Update prompted me to) and now with OS 10.6.4 I have gone for more than three weeks with consistently joyful results when waking the computer up from sleep.
Go figure.

I entered this discussion some time ago and shortly after that the problem disappeared on its own. Now after a month or more it has happened again. I am flabbergasted that no one at Apple has come up with a fix. I suppose I could get used to it but when you consider what you paid for this computer surely their technicians should be able to fix it. FRUSTRATED!

Me too! Bought my 21" i3 imac a couple of weeks ago so v.upset.
Never had this on my old G3 iMacs.

Hi again, I posted below 5 months ago about my discovery with an IO gear EXTERNAL Firewire HDD. Not once have I had the sleep issue again with me religiously unplugging the Firewire cable after each use. Two days ago I decided to retire the IO Gear Firewire and replace it with a Seagate 1tb extension USB 2 drive. Figuring I would leave that headache behind once and for all. Here I am two days later and the computer won't wake up. The IO Gear had an on/off switch, but still did not matter. The Seagate does not have a power switch and goes to sleep with the imac.
I am sure there are multiple Apple issues causing people to have different problems but hope this helps some people.
Mike

I'm so FRUSTRATED! I have tried everything suggested on this forum ‘wake up from sleep’ without success. This week I’ll be sending my iMac 21.5 back to Apple for repair and will also seek legal advice on how to deal with this problem in the future. In New Zealand we fortunately have a very good ‘Consumer Guarantees Act. Shame on you Apple.

I think I can help put this to rest...

Click the Bluetooth icon in the upper right.

Click "Open Bluetooth Preferences"

Click "Advanced" settings button in lower right of window.

Check box "Allow Bluetooth Devices to wake this computer"

I think for some reason, one of the OS updates un-checks this box. Simply re-enable it and you're set. This worked for me after having this issue for a few weeks.