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

been reading a lot about this, so wanted to throw in my own situation and ask for help.

Apple iMac, 27" early 2011 model (running Lion)

wireless keyboard and wireless mouse

The screen has been unable to waken from sleep for the past few days. I have tried it all - rebooting, external keyboards, etc. The computer its self is on, but the screen will not activate (yes I checked the brightness settings).

I read a lot online about turning bluetooth off (because of a bug with wireless keyboard and wireless mouse) yet without the screen working how could I do that?

I booted it into target disk mode, then using my MacBook Pro rebooted into the iMac's hard drive, started up the OS and turned off Bluetooth, I also enabled screen sharing.

So currently I am using my Macbook Pro screen sharing with the iMac to access everything. How funny that screen sharing works, but the iMac display will simply not turn off - further proof the hard drive, ram, etc on the iMac is totally fine, the display simply refuses to work.

Now for my plea - does anyone have any suggestions for getting my iMac display to work? I have a lot of video projects due soon and would really like them to be done on a 27" screen instead of a 13". Any suggestions are appreciated. I have full access to the iMac through screen sharing, so I'm willing to test out system preference tweaks, etc.

both computers are running latest version of Lion.

One thing that seems to make a difference on my iMac is the number of bluetooth devices turned on. I now only use the wireless keyboard and trackpad. In the past I had the keyboard, trackpad, mouse, and bluetooth speakers on all the time. In the past couple of weeks my screen freezing problem seems to have gone away. I couldn't find any other pref. that made a difference. It all started with moving to Lion.

This is partly in reply to Kingstonian and partly to provide a little additional information to my earlier post (11/28/11)...

On my work machine I am not using any bluetooth devices. Also, I haven't moved to Lion yet (still in Snow Leopard).

If any one has any ideas re: sleep mode causing keyboards (wired in this case) to stop functioning until either a) the keyboard is unplugged and plugged back in or b) the computer is restarted, please post them.

Thanks...

Mac Mini (Early 2009) 2Ghz 4GB RAM Snow Leopard with Monoprice Aquagate USB Hub 7 Port.

WORKS PERFECT

Mac Mini 2011 2.3 GHz 2GB RAM Lion 10.7.2 with Monoprice Aquagate USB Hub 7 Port.

Causes SUSTAINED and CONFIRMED crashes/shutdowns after trying to wake from sleep.

Not sure what is going on. I bought a Belkin 7 port hub today. All is copasetic now.

I have the problem too. The "Genius" at the Apple Store was very pleasant to chat with, but wasn't aware of this problem. My iMac checked out to be fine and he sent me home with no fix.

I inadvertently went through the procedure discribed by "canyonblue" and it worked for me.

I suppose my new iMac is Masonic since it seems to require a secret handshake.

Our problem with freezing and not waking has been resolved. We replaced faulty 3rd party RAM and all now have a perfectly functioning machine. This after Apple service replaced the logic board, bluetooth card and hard drive. Why they didn't test or replace the RAM I don't know.

In short, try replacing the RAM or remove any 3rd party RAM!

I wish I could blame it on the third party RAM, however this iMac was only a week old - only Apple products installed.

I have been using an external display for the past two weeks, punched out lots of video projects no problem. The computer runs like a champ; save for the monitor being completley dark. I am thinking the backlight has totally burnt out; going to back up and take it to the Apple store over the holidays and hopefully get it all sorted out!

True. 3rd party RAM is not the cause. This is an Apple problem. And this is not my first Mac to exhibit the display not waking from sleep. My old G3 laptop did the same thing, but with a lower frequency. My present Mac is only a month old, right out of box from Apple with nothing but Apple inerds --- and it has this problem. Very frustrating to spend thousands of dollars for a glitchy machine.

My "solution" is to turn off the auto computer sleep mode. I can still let the display go to sleep, but if the computer never sleeps then it woke have problems waking up.

However, I would like to know if anyone learns something useful that actually fixes this problem.

Apple replaced display and the logic board on my imac 27" late 2009.

The problem persist.. i've tried also with third part ram only and original ram only but without success!

My computer will be re-repaired next week and if problem persist replaced with new imac.

Ps. new display has yellow tint problem like the old one.

Hey guys. Do you have istat Pro widget installed?

I've noticed that after some tweaks in there and setting up screensaver, my imac behaves better.

No.. i'm sure that was an hardware problem. The display won't wake up also during lion installation.. i've tried everything. The only method that work, but for some hours, is PRAM and NVRAM clear.

Almakos,

What kind of "tweaks"? I have iStat Pro but I'm. Or sure what you did with it. Thanks!

in "General tab", I set S.M.A.R.T update interval to Off and in "Display" tab unchecked all disks and networks.

the initial problem in my case is because imac cannot fall asleep, just display turns off. For example if itunes is playing music or something is downloading, it may prevent mac from falling asleep, but display will still go to sleep mode. so just in that case it will be troublesome to wake it up.

Now it is rare that my mac won't fall asleep and screen sleeps, so I cannot wake it up, but still happens sometimes.

First stuff I do is press command + alt at the same time, in most cases works. If screen is still black, then I force mac to sleep with command + alt + eject and then it wakes up 100%

Thanks for replying! I have a feeling I might be experiencing a slightly different issue than you, though. It seems that my computer is indeed going to sleep, not just the display.

If the fixes I've tried so far (repairing disk and permissions from outside Lion, unpairing and repairing Bluetooth devices with fresh batteries, turning off "wake for network access" in Energy Saver prefs) don't work, I'll give your solution a shot!

Thanks again!

You are welcome

it is easy to find out whether mac is asleep

try adjusting volume or start music playback with keyboard. if there is sound and screen still black, then obviously mac is awake =)