iMac not waking up from sleep after Yosemite upgrade

Well...so far so good with El Cap. Bluetooth has been waking the computer again for me after sleeping. But I'm not going to hold my breath either. It's very frustrating to hear that you're still experiencing the problem. It makes me think that the underlying issue hans't really been fixed. And i'm sorry it's still not working for you.

I've been particularly frustrated with Apple care. They seemed very responsive at first but as I went through the steps with them, they couldn't fix it with the easy means. I was escalated to an advanced technician. He had me mess with the settings for a bit. I emailed him a lot of the console logs showing the issue.

He even gave me his email to send those files. Then I heard nothing for a week. Tried to email him a few times asking if there was any news (politely! I swear!) and heard nothing. Then finally 2-3 weeks later he emails me saying he's at training and to call back tech support. Okay....

So I did that. Talked to another guy recanting this same long story and reuploaded console logs and everything (still being very polite! I really do swear!) who said finally that he'd need to escalate this issue to engineering. "Great!" I thought naively. He said it'd take 3-5 business days. I heard nothing by a week so I emailed the guy. No response. I was busy with other things. Emailed him again a few weeks later at his Apple email that he gave to me figuring someone in engineering must have gotten around to it by then. No response. Tried one last time (yep. Politely.)...no response. So I called back tech support and they wanted to back through the whole thing again...and I said I'd try back in a bit because at this point I finally did lose my patience and hung up before getting testy.

Was a pretty lame showing from Apple support on this, what still may be, unresolved issue. If it starts happening again you (and apple) will hear from me.

If you need an affidavit that this is a problem, I'm happy to supply you one!

After upgrading to Yosemite, I've experience many video related instabilities on my mid-2011 27" iMac.

I took it into the Genius bar, and they ran a full diagnostic, because my iMac has a serial number that indicates it might have the Radeon video card bug, but they assured me that was not the case, and offered to do a format/re-install of the OS.

I agreed, and then restored from TimeMachine, but did not restore "settings and (something?)" which is supposed to prevent any wack settings from being restored. Things seemed to be going great! I wasn't getting the random crashes any more, but I started to get the black screen on wake from sleep issue.

So, a fresh install of Yosemite didn't help me. I have no external HD. I do have a NAS which I connect to the network. The interesting thing is that when it is in the "black screen" state, the screen would sometimes turn off, as if the screensaver was active, and pressing a key or moving the mouse would turn the monitor back "on" (I could see the black change from a powered-off black to a powered-on black, if THAT makes any sense), but nothing else would work.

Reset SMC didn't help.

I'm going to try to upgrade to ElCap to see if that helps.

Jake, I had this situation for two years. The workaround for me was removing the usb cable to my external HDD. When that was removed I had no sleep/wake problems. Now I've upgrade to 10.11 and lo and behold the problem is totally handled. So I suggest you do the upgrade and see if it helps you too.

GL

Unlike Emerald, I never had an External HDD and still had this exact problem. However, so far El Cap has been waking my computer successfully. I'm waiting for another patch to break it though which was what happened in Yosemite. Worked great until I updated to 10.10.3 and then the problem occurred. Time will tell to see how fixed it really is...

FWIW, I disabled sleep on my computer, and configured only the screen to turn off. So far, to recurrence.

I didn't do the upgrade to ElCap yet like I said I would, because I got spooked with the negative reviews....

Man this is really crazy...the samething happend to mine after upgrading to Montain Lion 10.8.5.

Now its working nornally during 1 month, and that's awesome ! Now its waking up from sleep right away.

The problem was ither the bluetooth mouse o keyboard. It was not working properly with any wireless o bluetooth device, not when trying to waking it from sleep.

I got the Track Pad from Apple, a Mouse from Logitech USB receiver with no luck, then I decided to use my wire mouse from my old windos pc. Guess what ??

From that day on is working fine ! Love it !!! The second thing I did, I changed the wallpaper, I used a darker one! Not to white or to bright. That made the magic..

No matter what you guys do after listening to Apple Support, nothing of that **** will work, I tried everything, i was from forum to forum trying to get awsers with no luck, I was about to break it ! Not kiddindddd.

Im pretty sure this will work from many of you...try, connect a wire mouse from now on and play with the bluetooth or wirelss mouse normally, keep the wire mouse connected all the time.

This applies to people who only have problem with the screen, black screen after waking from sleep.

Hope my history helps others, sorry for my English, hope u understood what I wrote.

Good luck !