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

I hope this helps, although I did not document every step I took, nor check for results between actions. I performed all of the following and the non-waking iMac 27" problem that plagued me stopped and has not returned in over a week:

1-Reset PRAM

2-Fixed permissions with Disk Utility

3-Used OnyX and ran all maintenance activities

I just bought my 21.5 " IMac back around the first of July with Snow Leopard installed. When Lion came out I immediately installed it and that's when this issue came up. It just would not wake up 1st thing in the morning. So had to use the power button to turn it off and back on. I happen across this thread and tried a couple of things.

1. Went into Systems Preferences> Network> and deleted the WiFi setting and then added it back in.

2. Went into the Disk Utility and ran Fix Permissions

3. Installed the 10.7.1 update.

I don't know which fixed the issue, but, I haven't had reoccurrence of this issue for a couple of weeks now.

Hope it helps

to find sleepimage in lion. I finder type G

then enter /var/vm this will should take you to the folder containing your sleepimage which is the same size as your ram.

I've tried what you suggested abd it took me to vm, but there I've found a single swapfile0, which is just 64 mb or so... no sleepimage, and my mac just woke up from night sleep.

before I tried to delete this sleepimage with terminal command but got the following:

"rm: /private/var/vm/sleepimage: No such file or directory"

and I have hidden files displayed, so don't know where it might be hiding...😕

I'm pretty sure only portables should have a sleepimage file. According to the man pages for the pmset command (the power management interface), the default for desktops' sleep is to NOT write memory to persistent storage.

That strange I checked and have sleepimage on all my macs (desktops).

Thanks for that. Now I'll never trust the man pages again!

I had this problem for a long time on my iMac 27/ Tiger. I finally found something that works for me. STOP USING THE SLEEP COMMAND ALTOGETHER! I put my puter to sleep the natural way! Go to your Energy Saver and set both your computer sleep and your screen sleep to ten minutes, or whatever time you want. This puts the computer to sleep ten minutes after I stop using it. When I return, I hit the keyboard and it wakes up, every time...no coma. This has been working for me for several months. Just walk away from your computer and it will put itself to sleep, and wake up refreshed.

My 2011 iMac i7 QC 16GB / 256GB SSD suffered from the same problems - no matter what I did, it would not wake up from sleeping.

I had to pull out the power cord and press the power button for some time - then I would start up again - after reattaching the power cord of course :-)

I tried a lot of the tricks mentioned in this thread - nothing helped until a friend recommended setting hibernatemode to force hibernation instead of just sleep.

I did this:

sudo pmset -a hibernatemode 25

I then did a normal restart.

Now, I can select "Sleep" from the Apple-menu - the iMac then hibernates in less than a second.

I wake it from hibernation using the power button - it takes 3-5 seconds - the power button must be used - keyboard, mouse or trackpad cannot wake it from hibernation.

I am sorry if this has been mentioned before - but it works for me - and none of the other tricks have.

- Tom

I should add that while I have no sleepimage, I set sudo pmset -a hibernatemode 0

and installed please sleep software. my display falls asleep after 15 minutes and mac after 30 minutes. should say that everything works so far so good...if I put mac to sleep with keyboard I then can easily wake it up. if it falls asleep by itself, then I can wake it up with command alt...** if something was working (like radio) when imac fall asleep by timer, then I still cannot wake up screen...because mac is not asleep actually, just screen is sleeping

I'm in the same boat with the rest of you. My iMac just started doing this in the last couple of weeks. It's really annoying. It is erratic...maybe 2 or 3 times/week after being in sleep mode all night. Hope someone finds a solution!

I have been plaged by this since last year, Apple came out with an update months ago to address this and it did help, my machine would not wake almost every day prior to the update and then would go several days and sometimes a week before failing post update. It seems network printer poll the LAN every ten seconds or so and somehow this is causing the post update problem. I have (had) Lexmark Pro-900 and now a HP6500Ae and they are both causing the Apple OS to malfunction.

Click on your hard drive icon, then "Library" scroll down to "LaunchAgents" click on that and drag or copy the printer files to your desk top (usually two files) "com.hp.****, then delete the two files from the LaunchAgents. Placing them on the desktop disables them and you can always return them. Both my printers still worked fine after removing the files and the iMac has been solid as a rock, finally. YMMV

I'm having the same issues after upgrading to Lion and replacing the hard drive with a Western Digital 2tb running at 7200rpm. I used to run into the wake up issue once in a few days but now it seems to be getting worst. Has anyone come across the same problem? Could this be related to the fan since the computer seems to run hotter with the new hard drive?

ENOUGH...I have been an Apple / Mac user since the Apple ll. This ridiculous problem should have been solved years ago, but Apple is now more interested in turning out spiffy commercial do dads, do pads, and do ****, than having their computers opperate correctly...I bought my first PC today, and unfortunately and very sadly, I may not be looking back. This is the Apple of the future...crap.

We had a problem with OWC SSDs failing to wake up after sleep timeout. We were advised to return them to OWC for "parameter reset". This was a long process that involved buying two additional SSDs, then cloning and swapping out drives two at a time for a couple of months. That did fix the problem, until this week, when it has started happening again. It seems like some Apple update "broke the fix", so now I am waiting for OWC to respond. In the meantime, we set Energy Saver to timeout "Never". The units can still be put into sleep mode by simply closing the lid.