10.12.4 display sleep bug

The display sleep bug returned on my system iMac 5K + 2xAcer DisplayPort monitors after about 24 hours unfortunately.

I have my ticket to WWDC so I'm going to have a chat with some MacOS folks there.

Maybe this will be fixed with MacOS Petaluma ;-)

Meanwhile back to never sleeping or just shutting down the system. At least with the SSD the system boots fast.

It is a bad idea (on any system) to mix memory brands - have even seen this kind of problem with Dells.

But I would postulate that most of the people posting here have memory either all from Apple (from the box) or all from a third-party like Crucial or MacSales since when you go third-party, you usually buy a minimum RAM configuration and upgrade all 4 slots.

Also, Mort, it sounds like you had a different problem since with the classic display sleep bug, the system does wake up but the iMac monitor doesn't turn back on. The other monitors may or may not turn back on (I just had it happen this morning and one of my external monitors came back on).

Earlier in the thread, binaryage said the first beta (10.12.6-16G8c, or 10.12.6-beta1) had not fixed the issue. Typically there are multiple releases of each beta. It's still possible that a subsequent 10.12.6 beta release will contain a fix.

So everybody knows: The priority of this fix will be driven by how much press it gets, and how many users create support tickets with Apple. Press on an issue like this is unlikely, but if you have AppleCare or are still in warranty, please be sure to create a support ticket with Apple and point to this thread. You can do that by phone or email on Apple's support site. If the support organization says this issue causes frequent contact from the users, the engineering leads will raise the priority.

As things stand, the couple people who have written about reaching out to Apple Support were told that Apple wasn't aware of this issue. The callers were put through the standard reinstall, reset controller, etc troubleshooting.

It's a terrible state of affairs when something as basic as external monitor use is unreliable.

I wish my 5k iMac was still under warranty. This bug is so frustrating. I want to report it, but don't know where. Either one of my 4k external monitors does not come back on, or the primary iMac display does not come back on after putting the screens to sleep. I can unplug the 4k and plug it back in to reset it, but nothing short of rebooting will fix the primary display. For such an expensive piece of hardware, this seems like a major bug. I have to reboot my computer at least once a day, and have to re-seat the 4k monitor display port cable several times. It definitely started happening in 10.12.4 and appears to have become a more frequent issue in 10.12.5 for me. I really hope this gets fixed!

With respect to "where" to report this bug, if you have an Apple developer account, you can log into the Apple Bug Reporter and report the bug. I met with an engineer at WWDC and he recommended doing a sysdiagnose when it is in the dark iMac monitor state and attaching that to the bug report. He took a quick look at the bug report database and couldn't find this problem so it is possible that no one was entered it (please reply if you have and have a bug report case number because I could bring that to an Engineer at WWDC today). He said that the AppleCare / Warranty channel is buffered too much from Engineering and that the best route was direct to the Bug Reporter.

The command-line utility

sysdiagnose

The issue still persists with the latest developer builds. I had rang Apple Australia about a month ago and was told Engineering was made aware of this issue. Further my previous post which expressed my displeasure with Apple was censored / removed. Not impressed that an expensive computer has such poor support. Not impressed at all!

This issue has been resolved for me, but I don't know how.

iMac Retina 5K, 27-inch, Late 2015 - macOS 10.12.5 (problem appeared after installing 10.12.4)

AMD Radeon R9 M395X 4096 MB

40 GB RAM (2 x 4GB from Apple + 2 x 16GB from OWC)

2 additional 4K Samsung U24E590 displays

I was getting ready to file a bug report as hmbay suggested, and performed the following steps:

1. Ran sysdiagnose with the system working (i.e. all displays working properly) with energy saver preferences as follows:

* Turn display off after - Never

2. Changed energy saver preferences as follows:

* Turn display off after - 10 minutes

* Prevent computer from sleeping - Unchecked

3. Waited until the computer went to sleep, then woke it up with the plan to run sysdiagnose again with the main display off... but the main display (and the two external displays) came on as they should.

The iMac has been working correctly for 4 days now.

The problem with this is (as far as I know) most of us have had the problem with just the displays going into sleep, not the iMac. Try selecting the "Prevent computer from sleeping" option and see if it happens. That is how my iMac was configured when I got the issue here. Displays turned off after x number of minutes and prevent computer from sleeping. Every time I try to wake the displays up only 1 or 2 of them come back but never all 3. This requires a reboot.

I just changed Prevent computer from sleeping to Checked and put the displays to sleep (by using a hot corner). All three displays came back as they should.

Unchecked the option again, put the computer to sleep and woke it up. All three displays came back.

The problem with my iMac had always been with the main display, and only a few times one (random) of the external displays. Most of the times both external displays came on, but the main display was always black after going to sleep.

Most times I was able to see the lock screen for a brief moment (one second or so), before the main display turned off and I had to reboot in order to be able to use it again.

Now that the problem is not happening, I have noticed that both external displays take a few extra seconds to turn on. One time it was long enough for the OS to move all windows from one external display to the main display.

I have monitored the Console before to try to find a log entry that could offer a hint about this problem, but there's nothing meaningful.

Tried to submit a report today, but unfortunately my developer account has lapsed and I don't have a need to renew it at this time. Did you ever get a chance to submit a report or get contact info for someone that can help get this in to the right channel?

Just to update... I did file a report on bugreport.apple.com but also (possibly because of contact at WWDC) I was contacted by a field quality engineer from Apple and I've connected him with my bug report. I'm going to call him next week when I get home to discuss the issue.

I have had similar experiences where it appears that the bug has been fixed. Don't be fooled. It will be back. There appears to be some sort of temporary situation where this bug doesn't occur for 2-3-4-5 days and then - bam - when you think all is going fine, the iMac monitor stays black. I had that happen while I was at WWDC and then on Friday the bug came back and I filed the bug report.

I emphasized the fact that many of us experiencing this issue are high-value, professional customers with expensive configurations and it was discouraging for us to experience this problem after what should have been a harmless OS update. I am getting a feeling that we will be seeing some activity on this issue.

Cheers, Joe

I sincerely hope so Joe. I fit your description of having a high end setup. At the time of purchase, it was the highest available configuration of the 5k iMac along with two 4K monitors. Nothing I have tried has solved the issue for good. The only work around I have now is setting my iMac to lock when screen saver turns on and leaving the screen saver on for a longer duration in hopes that I return before the screens sleep. Using a hot corner to activate the screen saver.

I've had my iMac 5K (i7 4GHz, 32GB RAM, 1TB SSD) for almost 2.5 years connected with 2 LG Thunderbolt 4K monitors. In all that time I've experienced the issue twice. I've been on 10.12.5 since it came out via all intermittent updates without issue.

Yesterday I've reinstalled the mac with erase and since then I am experiencing the issue as well. More than 10, 15 minutes of sleep and the internal display doesn't turn on, the external ones do.

Funny thing is that when I open Displays from the System Preferences I do get a window for the built-in display, but it gets displayed on one of the external ones.

I've chatted with Apple support and they still do those "reset the SMC and NVRAM"-suggestions. After that came: "testing it in safe mode without the external displays". According to "them", if "after performing a clean install there are still issues then it points to a hardware issue". I've asked how it can "still" be a hardware issue if there was none to begin with but no real reply to that. So I'm now stuck having to test this in safe mode before any further action is undertaken.

It's a real issue and front-line support and AppleCare do not have solutions.

If you have an Apple developer account, follow my instructions in an earlier reply and go to bugreport.apple.com and file a MacOS bug report like I did. Piling on will increase pressure.

If you don't have your own developer account, find a friend who has one so you can get this into the system.

And, actually, we're talking about a developer ACCOUNT - not a developer SUBSCRIPTION - so anyone can have a developer account and log in to bugreport.apple.com AFAIK. A developer subscription is what you need to publish apps. Just go to developer.apple.com and sign up your apple ID to become a developer.

As long as you have signed up as a developer, it doesn't matter that your subscription has lapsed - that's for publishing apps and support incidents. You can still use your developer account to log bugs AFAIK.