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dpavid

macrumors regular
Original poster
Feb 17, 2004
135
9
Mililani, Hawaii
Model Name: Mac Pro
Model Identifier: MacPro6,1
Processor Name: 6-Core Intel Xeon E5
Processor Speed: 3.5 GHz
Number of Processors: 1
Total Number of Cores: 6
L2 Cache (per Core): 256 KB
L3 Cache: 12 MB
Hyper-Threading Technology: Enabled
Memory: 32 GB
System Firmware Version: 425.0.0.0.0
SMC Version (system): 2.20f18

My displays won't wake up. I have energy saver turn the display off after 15 minutes. Nothing turns the display back on. I also have prevent computer from sleeping enabled, wake for network access, and
start up after power failure enabled. Thanks in advance for any help.
 

astrorider

macrumors 6502a
Sep 25, 2008
534
60
What displays are you using? I had a Dell 5k that had similar problems with waking from display sleep whenever the monitor's own Energy settings were also set to sleep. On the Dell this was under Menu > Energy > Monitor Sleep. Setting that to "Disable" would fix it.
 

dpavid

macrumors regular
Original poster
Feb 17, 2004
135
9
Mililani, Hawaii
What displays are you using? I had a Dell 5k that had similar problems with waking from display sleep whenever the monitor's own Energy settings were also set to sleep. On the Dell this was under Menu > Energy > Monitor Sleep. Setting that to "Disable" would fix it.
Nothing. The computer is in sleep mode and monitors confirm by blinking white LED. Has to be Mac OS issue.
 

jazz1

Contributor
Aug 19, 2002
3,303
3,255
Mid-West USA
I’m not sure if I have the same issue, but I have a 27” iMac 2015 with two external Dell monitors. Since installing Big Sur public release, all three screens take a long time to wake up. This didn’t happen in the beta Big Sur.

It actually if pretty odd as the computer/screens wake up. I get an initial desktop background, then all three go black, then running apps appear on a black background. Eventually all running apps appear and then the desktop background shows up.

Note, I have been running my iMac without background updates while sleeping. I was having wake up crashes under Catalina. Today I did turn on background updates while sleep. I don’t know if that will help with this issue. Who know maybe my old Mac is having issues unrelated to Big Sur?
 

TechnologicallyChallenged

macrumors newbie
Nov 19, 2020
2
0
I’m not sure if I have the same issue, but I have a 27” iMac 2015 with two external Dell monitors. Since installing Big Sur public release, all three screens take a long time to wake up. This didn’t happen in the beta Big Sur.

It actually if pretty odd as the computer/screens wake up. I get an initial desktop background, then all three go black, then running apps appear on a black background. Eventually all running apps appear and then the desktop background shows up.

Note, I have been running my iMac without background updates while sleeping. I was having wake up crashes under Catalina. Today I did turn on background updates while sleep. I don’t know if that will help with this issue. Who know maybe my old Mac is having issues unrelated to Big Sur?
I have the same issue. Is Cupertino listening?
 

Takeo

macrumors 6502a
Nov 10, 2004
712
329
Canada
Same issue here. Brand new MacBook Air M1 + an old BENQ 2560 x 1440 display that was connected to my old 2015 MacBook Air on Catalina via Mini-Displayport to HDMI. With the new MacBook Air the connection is via the Apple Multiport Adapter with a HDMI to HDMI cord. I've tried changed the HDMI cord. No luck. Still refuses to wake the monitor from sleep (no signal detected). But not always. I just went into the on screen menus of the display and found a HTML "auto on" feature which was off. Turned that on. Hopefully that fixes it. BUT... that was never on before and it worked fine on Catalina with my 2015 MacBook Air.
 

Takeo

macrumors 6502a
Nov 10, 2004
712
329
Canada
p.s. I'm going to be upgrading the display to either a Dell Ultrasharp 34" (U3419) or the Asus ProArt 34" Ultrawide (leaning towards the latter). Both displays have USB-C. Maybe a USB-C connection will be more reliable for waking from sleep.
 

jan48

macrumors newbie
Dec 2, 2020
4
4
I have the same issue. Got my MacBook Pro M1 yesterday and my Apple Thunderbolt Display doesn't come alive after the sleep mode.
 
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jan48

macrumors newbie
Dec 2, 2020
4
4
I have something that can function as a workaround. Besides the monitor I had a USB-C hub connected. As soon as I pull the hub cable from the Mac the screen wakes up right away. Maybe that works with some users. I don't have to reboot the systeem anymore to get the monitor working.
 
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dotz

macrumors newbie
Dec 26, 2020
2
0
Hey @jan48, I have the same issue: I connect my monitor with Apple's AV Dongle with HDMI 2.0 and HDMI cable and everything works fine until I put my computer to sleep, then the monitor won't wake up. Clamshell mode works, the computer is being woken (as I can see from my Apple Watch, it gets unlocked), but there's nothing on the display. As soon as I disconnect the dongle and connect it again, it works. As long as I don't put the computer to sleep. Today's update to 11.1 did not fix anything. I'm waiting for Thunderbolt USB-C to DisplayPort adapter. Will let you know if that helped.
 

jan48

macrumors newbie
Dec 2, 2020
4
4
The 11.1 update did solve the problem for me. The external screen works fine now after waking up. Using Apples Thunderbolt USB-C to DisplayPort adapter.
 

VikasB

macrumors newbie
Jan 3, 2021
1
1
I have the same problem and even after update to 11.1 this is not resolved. I have a Mac 27" and using a ViewSonic vx2255wmb monitor as my second monitor. Every time I have to put the system to sleep and wake up multiple times before the second monitor turns on. Please help!
 
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dotz

macrumors newbie
Dec 26, 2020
2
0
@VikasB , get a USB-C (Thunderbolt) to DisplayPort dongle and use Display Port. Even if latest Big Sur update fixed not-able-to-wake-up-while-in-clamshell-mode-with-ext-display issue for me with HDMI, I find HDMI to be slower (when waking up) than when connected with DisplayPort.

Make sure the cable is certified to handle 4K @ 60 Hz.
 

MikesMac267

macrumors newbie
Sep 26, 2020
2
1
Canada
I've had this problem for months. 2020 iMac with Radeon 5700. Two external displays: Dell U2414H and P2719H. On 11.1 update.

I did a SMC reset and the problem went away for several weeks until today. I also had one display randomly turn off while I was working, then come on again.

I was using USB-C to HDMI and switched to DisplayPort and it seemed a bit more responsive, but only on the times it would wake up at all. Otherwise I had to unplug and plug the monitor back in, or restart.
 
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Bustermd

macrumors regular
Apr 21, 2020
101
233
Having this issue with LG 4k Ultrafine display purchased from Apple.
Macbook Pro 13 inch Intel 10th gen 2020 in clamshell mode.
If computer goes to sleep, can't wake display. Have to unplug display and open laptop. Sometimes can be fixed by plugging the monitor into a different thunderbolt port, sometimes not. Sometimes laptops screen goes crazy and flashes/flickers constantly. Only thing that "fixes" the issue is rebooting the laptop. Resetting SMC and clearing NVRAM made things worse.

And its not just that the display won't turn on, the computer literally loses the connection. It still charges from the monitor but it does not show up as anything being connected to the thunderbolt port in the system report, and using the Detect Displays trick in system preferences doesn't find anything. Occurs on all four ports. Also, the internet is full of people having various permutations of this problem, including with Thunderbolt Docks (like the CalDigit which Apple certifies as "compatible" with their devices), which leads me to believe this is not in fact a problem with my hardware but a software issue, specifically with Big Sur.
 
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flowrider

macrumors 604
Nov 23, 2012
6,766
2,627
^^^^I'm on Big Sur 11.2. My Mac is a 7,1 NcMP. Using the same Mac LG 4K Monitor. I don't usually use sleep, but just tried it and I do not have any issue. Wakes up fine.

Lou
 

Bustermd

macrumors regular
Apr 21, 2020
101
233
^^^^I'm on Big Sur 11.2. My Mac is a 7,1 NcMP. Using the same Mac LG 4K Monitor. I don't usually use sleep, but just tried it and I do not have any issue. Wakes up fine.

Lou
The computer has to be in sleep mode for a bit (half hour or more) to experience the issue. Also I’m on 11.1. If 11.2 has a fix for the issue I’d be ecstatic.
 

Mayhem SWE

macrumors newbie
Sep 22, 2020
11
4
Stockholm, Sweden
I have an old MacBook Pro 15" 2016 with two monitors, one Lenovo P27u connected through USB-C and a Y27q connected by HDMI through a dongle. After deep sleep the latter monitor flashes to blue all over the screen every five seconds or so, unplugging and replugging fixes it but still irritating. Just got the notification of a 11.2 public beta being available so will try to install later and see if it improves things or not.
 

A.Chakery

macrumors member
Aug 27, 2011
78
8
Vienna, Austria
Hi,

I have a MacMini 2018 and I am experiencing this issue from the beginning which I upgraded to BigSur. Now I am on 11.1 and still having the same issue.

I have 3 Displays, One Apple Thunderbold display, One HP1080 and one LG 4K.

I am experiencing this issue with LG4K which is connected to the HDMI port.

Any suggestions ? has anyone had been able to resolve this issue ?
 

Macdog59

macrumors newbie
Aug 23, 2012
4
0
I had the same waking from sleep problem. I have multiple monitors in my home ,both G-Sync and Freesync versions.My experience was when using a G-Sync monitor my mini would not wake from sleep and would only display after power cycling it. The problem went away when I replaced it with a Freesync monitor. I wonder if Nvidia has not updated their drivers for Catalina and Big Sur?
 

besht2003

macrumors newbie
Feb 28, 2020
8
2
People are reporting variety of display issues with Big Sur besides sleep mode--particularly loss of HDMI port and some report losing USB-C to HDMI connection. SMC reset may or may not work and if works may or may not hold. Mine is Mac Mini 2018 with gamut of Big Surs including betas. Apple is for sure aware and either helpless to fix or has other priorities.
 
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peterlemer

macrumors newbie
Nov 27, 2014
4
0
iMac 2019 i9 and Dell U2913WM.
Similar to many above, iMac on wakening from sleep mode, the dell is unresponsive.
If I unplug the Displayport cable the Dell comes back - most of the time.
Sometimes the DELL remains unresponsive and I need to unplug it from the main supply, wait, and reconnect, It then comes back on.

This suggests to me that there is a problem with the iMac. Maybe it sends a signal to sleep external mac displays, which then affects the DELL.

The DELL remembers sleep mode and is waiting for a wake signal, but doesn't recognise the Apple version, so it needs unplugging to come back to life.

I am reluctant to buy another monitor, as this one is great, and there's no quarentee a replacemnt will be better, unless, of course, it's an apple display. Crowdfunder beckons :-(

I'm playing with the Dell DP settings to see if this helps. ( using the Dell manual)
 
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