black screen after sleep

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Level 2

159 points

black screen after sleep

My iMac usually won't wake up after sleep; I get a black screen and have to force it to restart. This started when I got my new M1 iMac and transferred from my Intel iMac using Migration Assistant. What I've tried, and some clues as to my problem:

• It only happens in my user section, not the other user (also admin).

• I reinstalled macOS over the previous OS.

• I removed all login items and removed everything from my user Library's LaunchAgents folder.

• I disconnected all external things (backup drives). I have no hub or anything.

• I talked to Apple Support and sent them logs, and they said it appears not to be a hardware issue.

• I ran Disk Utility from Recovery; no problems found.

• My Notification Center also didn't work properly (I couldn't edit widgets); I ended up resetting it via Terminal, and now it works.

• I would intermittently get a warning, when syncing my iPhone, that USB accessories were using too much power, even though the only thing connected was my phone. Haven't had that warning in a while, though, so maybe the last update fixed it...?

• I tried (in System Settings) preventing automatic sleeping when the display is off and not allowing the display to turn off, but the issue still occurred.

• This may be unrelated, but Console's system.log shows hundreds of entries (about 1/minute) like this:

Apr 26 00:01:29 purpleiMac MobileDeviceUpdater[81414]: Entered:__thr_AMMuxedDeviceDisconnected, mux-device:3447

Apr 26 00:01:29 purpleiMac AMPDeviceDiscoveryAgent[78715]: Entered:_AMMuxedDeviceDisconnected, mux-device:3447

I'm hoping this issue can be fixed without having to erase the computer!! Could a corrupted preference file be causing this? I saw something about deleting /Library/Preferences/com.apple.powermanagement.plist, but I have 3 such files and they're for the whole computer, and the other section seems to be fine, so I don't know.

Any help would be much appreciated!!

iMac (M1, 2021)

Posted on Apr 26, 2023 6:28 AM

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Answer 1

Top-ranking reply

DonnaR Author

Level 2

159 points

May 8, 2023 7:35 AM in response to Old Toad

I have obviously not forgotten! I haven't posted because I was waiting to see if I'd really figured out how to prevent the issue (not being able to wake from sleep), though I don't know the underlying cause.

As mentioned, my Mac's Console log had hundreds or even thousands of entries each day, which I figured had something to do with my iPhone. And I'd gotten warnings when syncing about the iPhone "using too much power," even though I don't have a hub (and I tried different Apple-brand cables).

Once I unchecked "Show this iPhone when on wifi," the Console errors immediately stopped ... and the computer hasn't "frozen" since then -- 10 days ago!!

BUT when I connect my iPhone (XR), I still sometimes get the error about USB accessories using too much power, even though they shouldn't be. I sent logs to Apple Support and they said they didn't see a hardware issue, but what else would cause an error about using too much power??

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Answer 2

Old Toad

Level 10

216,854 points

Apr 27, 2023 1:52 PM in response to DonnaR

Download and run Etrecheck. Be sure to give it Full Disk access before running.

Copy and paste the results into your reply. Etrecheck is a diagnostic tool that was developed by one of the most respected users here in the ASC and recommended by Apple Support to provide a snapshot of the system and help identify the more obvious culprits that can adversely affect a Mac's performance.

Copy the report

and use the Additional Text button to paste the report in your reply.

Then we can evaluate the report to see if we can determine the cause of the problem.

In the meantime a quick and easy workaround to not enable this slide switch and just use your screensaver:

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Answer 3

Old Toad

Level 10

216,854 points

Apr 27, 2023 3:42 PM in response to DonnaR

DonnaR wrote:

Thank you so much, Old Toad! I've seen you on these forums for years; you must have helped countless people, and it's an honor to get a reply from you.

The issue of not being able to wake up from sleep persists, even though in System Settings I've:

turned off "Put hard disks to sleep when possible" in Energy Saver,

turned on "Prevent automatic sleeping when the display is off" in Displays / Advanced, and

put "Turn display off on power adapter when inactive" on Never!

Give this a try: boot into Safe Mode according to How to use safe mode on your Mac and test to see if the problem persists. Reboot normally and test again.

NOTE 1: Safe Mode boot can take up to 3 - 5 minutes as it's doing the following;

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts

• Deletes font caches, kernel cache, and other system cache files

NOTE 2: if you have a wireless keyboard with rechargeable batteries connect it with its charging cable before booting into Safe Mode. This makes it act as a wired keyboard as will insure a successful boot into Safe Mode.

There is no personal info in the report. It even goes to the extreme of hiding names of hard drives if they aren't the default Macintosh HD - Data. Like for my Toad Hall drive it shows as T*******l.

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Answer 4

DonnaR Author

Level 2

159 points

Apr 27, 2023 1:14 PM in response to DonnaR

Kind of disappointed that no one has replied, but I thought I'd update my post anyway in case it helps anyone else:

I figured the Console log's error messages had something to do with my iPhone. Once I turned off "Show this iPhone when on wifi" in Apple Music, the Console error messages immediately stopped.

I doubt that issue has anything to do with the Mac not being able to wake up from sleep; stranger things have happened, but it doesn't seem likely.

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Answer 5

interact

Level 1

50 points

Apr 27, 2023 1:22 PM in response to DonnaR

This is different, but today I had an issue where the built in screen would go black after login and only the external monitor would be visible. The issue persisted after restarting. I was not able to see any windows that were on the MacBook Pro screen. It was really troublesome. I finally just closed and opened the laptop and the screen came back on. Perhaps there's a bug in the current OS 13.3.1 (22E261)

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Answer 6

DonnaR Author

Level 2

159 points

Apr 27, 2023 1:39 PM in response to interact

Thank you for responding!!

I have an iMac (desktop) so I can't close and open it like a laptop, but interesting that that worked for you! My issue has occurred since before this version of the OS; I was hoping that an update would fix it, but it didn't.

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Answer 7

DonnaR Author

Level 2

159 points

Apr 27, 2023 2:01 PM in response to Old Toad

Thank you so much, Old Toad! I've seen you on these forums for years; you must have helped countless people, and it's an honor to get a reply from you.

The issue of not being able to wake up from sleep persists, even though in System Settings I've:

turned off "Put hard disks to sleep when possible" in Energy Saver,

turned on "Prevent automatic sleeping when the display is off" in Displays / Advanced, and

put "Turn display off on power adapter when inactive" on Never!

One question before using Etrecheck: Would posting the results share any personal information about my computer? In other words, would posting the results open me up to potential hacking or identity theft? Just want to make sure.

Thanks very much again!!

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black screen after sleep

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