Macbook Pro 16 M1 not waking up external monitor

• on invoking Option-(Detect Display) button in Displays preferences (from another display)

System Preferences > Displays ...

hold the Option key and the (Detect displays) button should appear.

Click it. your additional displays should spring to life.

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Users are reporting display recognition works somewhat better in macOS 12.5.1. ¿are you fully up-to-date?

to get a Mac display to become active, you need the Mac to query the display, and the display to answer with its name and capabilities. Otherwise, the display will not be shown as present, and no data will be sent to the display. "No signal detected" is generated by the DISPLAY, not by the Mac.

This query is only sent at certain times:

• at startup

• at wake from sleep — so momentarily sleeping and waking your Mac may work

• at insertion of the Mac-end of the display-cable, provided everything on that cable is ready-to-go

• on invoking Option-(Detect Display) button in Displays preferences (from another display)

so try doing some of those things and see if the display comes alive.

Modern Displays with multiple ports are sometimes busy scanning the other ports, looking for an input, and miss the query from the Mac. They need to pay attention to the port you are actually using, or they will miss the query.

Some displays have On-Screen Display settings that can be used to tell the display a computer is attached on a certain port, or a certain port should be highest priority. Changing those may make your display more responsive.

Some displays include their own private "sleep" settings for the display alone. This can allow the display to enter its own sleep mode, on top of the Mac's not sending it data. A display that is sleeping on its own cannot respond to the Mac's query, and will stay dark.

OMG! They have finally seem to have fixed it! Well I definitely improved it - I have just updated to 12.5.1 and have put my Mac to sleep 5 or 6 times and let the monitor go to sleep and every time it has woken up and woken the monitor!

As I said it's improved but I still did cause the issue on one time when I woke the MacBook up when the monitor was in scanning for signal and it didn't sync up and bring the screen back correctly. However, in general use that'll never happen since my main gripe was whenever I am away from my desk for a period and return to it all asleep and having to mess around waking/logging in/put back to sleep/waking again.

Finally, after nearly 2 years the M1 MacBook almost has full USB-C monitor support! :-/

Ok - so I got through to a specialists and this problem seems to be accepted that it exist in general - however - I am currently testing a possible fix and so far in the past couple of hours since I did the fix, it does appear to have fixed my issue.

However, the Case is still ongoing and I will be testing it over the weekend - what we did was to delete the com.apple.windowserver.plist file from the /Library/Preferences and then deleted com.apple.windowserver.<Hex String>.plist file from the Hidden Library/Preferences folder (on the Finder Go menu press the Option key to access it), then restart the Mac.

As said the case is ongoing and I will test it more over tomorrow and weekend to see if it's a full fix but from initial testing it seems to have improved matters. Previously if put the mac to sleep and woke it up whilst the monitor had not fully gone to sleep (still showing Scanning for Signal) then I could replicate the issue, but since doing this I can no longer replicate it. Also after my lunch break I came back to the Mac woke it up and it had no issues . . . .

So touch wood, this could be the fix we are looking for.

I have been suffering this issue with my MacBook Pro 13" from the beginning - each time I hope that the absolutely hopeless usb-c monitor support is fixed in the latest OS update, but it never is.

The main issue is that it's not 100% consistent. The MacBook goes to sleep then when you wake it, my external screen will come on but then disconnect or it just won't come on at all, then the other times it wakes up and work immediately. This is with a Dell 27" monitor and a Hyperdrive 12 port hub, but I have also tested it with a standard USB-C video out cable and it has the same issue.

The work around I have been doing is just put my MacBook asleep and immediately awake it with a mouse move or key press and it'll fire the monitor up every time.

I just find the whole thing highly annoying and frustrating given windows pc have been supporting multiple external usb-c displays for years with zero issues, however Apple just seems to point blank refuse to fully support usb-c's full functionality and try to push thunderbolt on to everyone.

I have a 100watt USB-C psu running my dock station with 85watts being fed to the MacBook so it certainly is not linked to lack of power.

Also Jeffd55 there is no point recommending resetting the NVRAM as Ramgs clear states he has an M1 based MacBook Pro.

Hello Ramgs,

To help isolate the cause of this issue. Create a new user account and test to see if the same thing happens. This will determine if the issue is within the entire system or just your profile:

Set up users, guests, and groups on Mac - Apple Support

Add a user

1. On your Mac, choose Apple menu  > System Preferences, then click Users & Groups 

2. If the lock at the bottom left is locked , click it to unlock the preference pane.

3. Click the Add button  below the list of users.

4. Click the New Account pop-up menu, then choose a type of user.

If the issue persists, reset the NVRAM on your Mac. This can help resolve issues such as sound volume, display resolution, startup-disk selection, and time zone:

Reset NVRAM on your Mac - Apple Support

Best Regards.

So is this what you did?

For MacOS 12 Monetary, you got some relief by deleting two preferences files, then Restarting:

/Library/Preferences/com.apple.windowserver

~/Library/Preferences/com.apple.windowserver.<UUID>.plist   -OR possibly-

~/Library/Preferences/ByHost/com.apple.windowserver.<UUID>.plist 

-- where [~] tilde is an active abbreviation for "current user"

-- and <UUID> is a string of hexadecimal numbers unique to your system, grouped as 8-4-4-4-8 hexadecimal digits

Restart REQUIRED after these deletions (so that the System will re-create those plists in the correct form).

/Library/Preferences/com.apple.windowserver.plist

~/Library/Preferences/ByHost/com.apple.windowserver.<UUID>.plist 

They were the two file deleted.

Things have improved, but sadly it's not a fix, I have had the screen fail to awaken twice since doing it - so will be speaking further with Apple on the subject.

Grant Bennet-Alder wrote:

Users are reporting display recognition works somewhat better in macOS 12.5.1. ¿are you fully up-to-date?

At that point your replies become pointless since you obviously have not read the whole thread.

Grant Bennet-Alder wrote:

Communication is a two way street. If you find my replies are not in line with what you need, there's a 50-50 chance it is your descriptions of the problem are the reason.

What??

If you read the whole thread you would see that both myself and Ramgs actually replied to the thread stating we saw some improvement with 12.5.1. The descriptions given in this thread are clear and detailed if you cannot understand them that's not my problem, but don't just post generic troubleshooting methods it helps no one.

Back to the topic -

@Ramgs - something you might want to try is changing your external screen to the Main Screen under Sys Pref > Displays > Display Setting (that is if you've not already done that). I did it this morning when looking around to see if there was any settings that might influence things and since doing it the display has woken up from Sleep several times without issue - so worth a try.

@Ramgs - something you might want to try is changing your external screen to the Main Screen under Sys Pref > Displays > Display Setting (that is if you've not already done that). I did it this morning when looking around to see if there was any settings that might influence things and since doing it the display has woken up from Sleep several times without issue - so worth a try.

Scratch that - just did the same thing - so back to square 1.

At this writing, this discussion has been viewed over 150 times. No additional work-arounds seem likely to be forthcoming from this discussion.

It's time to contact support and work through the simple stuff until you can ask for a specialist. Have them file a bug report or add you to an existing Bug Report.

Get Support

.

Then you have failed to adequately articulate what your real problem is.

Try again, as if explaining to a small child:

what steps do you do?

what results do you expect?

what happens instead?

also:

what exact display?

what docks adapters and cables are being used ? -- please mention every item.