Q: sleep wake problem with Yosemite on my Mac Mini Mid 2012

https://support.apple.com/kb/DL1828?locale=en_US

I had received a update notice from Apple about my Mac Mini 2012's EFI firmware 1.8 this morning.

After update that EFI firmware, my monitor's sleep not wake problem solved.

Before I solved this problem, I had turned off my DVI monitor's sleep setting in System Preference's Energy Saver for months.

Chen, that's the update I received and I'm happy to report that I let it go into deep hibernation today and it did not freeze when I woke it. Success! Thank you Apple Engineers. I love you again, Apple. Apple rocks! I'm never going back to you Bill Gates. Never. Apple was always the place for me and it took me too long to figure that out. So many wasted years.

I bought my 2012 Mac Mini Server new from Apple in December 2014. I updated to 10.10.4 this morning and then the EFI 1.8.

As hard as I've tried......still not able to get it to freeze or randomly restart on wake.

FINALLY.... it took Apple 8 months plus to com up with a fix.

NOT SO FAST......10.10.4 seems to be CAUSING sleep wake kernel panics when waking with the Apple USB keyboard. Didn't happen with 10.10.3.

I am having sleep wake issues with my MAC mini 2012 and Yosemite 10.10.4, I have not tried the firmware yet, but I did kill the hibernate image file using Sudo and hibernatemode=0 - so far no issues. I only want  the mini to standby, not go into hibernate mode.

Agreed. Have had my quad core mac mini 2012 for a year with no problems and since roll out of efi update and 10.4.4 it is now hanging waking from sleep with my usb wireless mouse/keyboard.

My quad core Mac Mini 2012 seems to have developed this hang at login screen after wake from sleep (it shows the login "screen" but there is no login box/buttons .. have to power cycle to get out of it) since the EFI update - I don't recall it happening previously.

I really hope Apple can get this sorted. I've sent product feedback as recommended up thread.

I've done everything suggested/recommended to prevent sleep/wake crash. All the updates, new hard drives, new RAM, bluetooth off etc. Still crashes on sleep/wake. So.....I don't put it to sleep anymore.

I have had a trouble free run with my Mac Mini late 2012 (OSX 10.10.4) quad core until it recently (around mid October 2015) developed a waking problem from sleep. Used to be able to wake it in the morning after sleeping all night with a touch of the Apple USB keyboard or touching my wireless mouse. Now it will only start up from a long sleep with a touch of the power button. Then I get a translucent white screen (I can see my windows open on the desktop behind that) and a start-up bar before it kicks back into life - takes a few seconds before we are up and running again. Oddly, this problem only occurs after a long sleep, like over night.

Also noticed from watching Activity Monitor that the HDD then gets really busy (at some Kernel level process) reading and writing little amounts of data. It's constantly chattering away in the background when nothing else is going on. I am sure this is part of the problem - someone in a previous post in this thread described it as a 'kernel crisis' which seems very apt.

Spent over 5 hours on the phone to Apple trying to resolve this - no one mentioned it was a known bug bug but instead advised me to do a clean OSX reinstall - which I did, was trouble free for a little while, and then same problem returned after a few days.

The problem can escalate to such an extent that if I run a cloud based back-up, it constantly has to re-sync with files being changed on the HDD. This means there is up-down comms going continuously which slows any work requiring internet. Also can affect the speed at which windows and files get opened on the machine. So had to disable that.

I also noticed this problem started to affect my Macbook Air (2011) around the same time and sometimes it just refuses to wake now after I have been using it only minutes before - only way to deal with this is a hard power down and re-boot.

What to do?

I had same problem: Mac Mini 2012 freezing, not waking up. Happened with Yosemite and El Cap , but not with Maverick. Tried clean install several times. Only thing that finally worked was decoupling fusion drive I had created; no problems since. I don't know if this applies to anyone else, of if anyone would want to go to all the trouble to do this, and I have no idea why this helped, but I just thought sharing my experience might help someone.

Does it work not putting it to sleep. I had this problem this past summer and now it's happening again. I updated to El Cap thinking it would solve it this time, but it hasn't. This time it's a combination of the Monitor, which is an ASUS 27" and various applications. Upon waking from deep sleep, if I get this far, if I try to activate Safari or any other application I get the spinning wheel of death and I have to force it off with the switch on the back of the Mac Mini 2012. Please guys, this is ridiculous. Several reports of the kernal panic reports have been sent to Apple, so I know the engineers are aware of this. Please send the update with the appropriate device firmware updates so we don't have to keep experiencing this.

I was having aa similar problem with my mac mini. It was losing its internet connection every time it went to sleep. Not the "greenest" solution but I solved it by the following:

1. Open "System Preferences"
2. Select "Energy Saver"
3. Select "Never" on slider for "Computer sleep;"

That may do it. It worked for me.

I know it's an old thread, but adding this just in case it helps somebody. My Mac mini would not go fully to sleep - the screen would shutdown but the CPU did not. None of the suggestions in this thread helped. Finally determined it was an external backup drive connected via FireWire that was somehow communicating with the CPU, preventing entry into the sleep state. Disconnecting the device allowed the CPU to enter sleep mode, not a convenient option.

The bad news, I have not found a fix (would probably require driver change on hard drive manufacturer's part).

The work around: in power settings, drag the CPU timeout to 1 minute. Within a couple of minutes, the machine went into full sleep. When bringing back up, drag monitor timeout to the right (it will drag CPU timeout along).

Yes, it's kludgy, but after 1+ years of frustration, I am happy to have finally found something that works.