External Monitor Issue After macOS Sequoia 15.1.1 Update

Thank, and Happy Thanksgiving to you, too!

I can confirm that this dock does rely on DisplayLink, and that could be part of the problem.

As far as I can tell, you are downloading from the proper location. They do say they support Sequoia.

I don't know if it is something with the software or the dock itself, or a combination of the two.

Can't really say for sure, maybe a couple of days after the update that I noticed the issue. I don't spend a lot of time on my Mac during the work week. I'm mostly on my work Windows laptop until the weekend so I didn't plug it in to the Mac until a few days after the update. Plus, I didn't spend a lot of time troubleshooting. I plugged the old dock back into my windows laptop after the issue started on the Mac and all seemed fine. In the end, I can't really be sure it was the dock or the Mac update. All I can say for sure is that the new dock works fine on my Mac. So, I'm happy and it ends there, for me at least. This may not be the solution for everyone, but it may be for some.

Same issue for me the moment my MacBook Pro update to 15.1.1. LG monitor flickers and comes on for a second then black screen. Worked flawlessly up until now and I've tested several other monitors with the same results. since I use an external monitor for work all the time. Seems like this would be a massive widespread problem. Hope this gets noticed and fixed asap!!

[Edited by Moderator]

Similar issue with an M1 Max MBP with 2 external displays. One external falls asleep while I'm actively working and the other external does not. Both were functioning perfectly prior to upgrading to Sequoia 15.1.1.

I have both a Viewsonic and a Samsung external and I see the issue in the Samsung. It’s pretty clearly a software quality issue unless a lot of displays from various manufacturers owned independently by users all over the country/world all failed coincidentally immediately following a software update from Apple.

This kind of stuff is why I never take X.0 releases from Apple anymore on any platform. The fact that this is happening in 15.1.1 just tells me the quality control has only gotten worse.

Hi all,

Same issue here --> Macbook Pro 2018 Intel I7 with T2 Chip

• Happens with:
  • Original Apple USB-C to AV digital (see screenshot)
  • Other USB-C HDMI adaptors
• Tried
  • Change cable
  • Change adapter
  • Change refresh rate
  • Reset NVRAM
  • Reset SMC
  • Pray....

Nothing works, have we an estimation of when this issue will be solved?

Regards.

I have MacBook Pro 16" 2021 plus external monitor and iMac 2019 plus external monitor, both machines used for work in situations where a second monitor is essential. Both updated to Sequoia last week. No problems with the iMac external monitor but the MacBook external monitor keeps blacking out as described by others. It seems fine as long as I am working on something on that second screen but will disconnect itself when it hasn't been used for a few minutes. The only way to reconnect seems to be the classic unplug/replug and that doesn't always work.

I have no technical ability or available techie and it's really making life difficult and interrupting the workflow. When will Apple fix this?

Same here. I thought my monitor was failing but realized it happened after a Sequoia update. Flickers off for 2 seconds every few minutes, kills my audio coming out of the monitor as well during that time, which usually happens when I'm in the middle of an important Zoom meeting for work of course.

I am having the same problem with my MackBook Pro and my Vizio monitor. I had a TV screen that had a defect on it and I use it as my second monitor. It has worked seamlessly for several years. No problems until I updated to Sequoia. It tells me no signal even thought shows in System Prefs and is set to correct input. I've checked cables, etc. Nothing works.

Experiencing exactly the same: iMac 2022, external display via DVI/Thunderbolt. Ran for 3 yrs without any problems, after updating to 15.3 yesterday all went down. Ext display constantly switching off for ~5sec and on again after. Follows no logic, happens occasionaly every 2 mins, then 1hr everything is good. Tried every described solution, nothing changes.

Is there any chance that someone from Apple comes accross this discussion and does sthg against it?!? Work is almost not possible like this

Didn't work for me.

Just tried this with my wife's MacBook (M1, 8GB RAM, Sequoia 15.3.1 - she doesn't need an external monitor) and the same LG 29UM69G monitor:

• Connected the LG monitor for about 10 minutes, problem manifested
• Hard-deleted `/Library/Preferences/com.apple.windowserver.displays.plist`
• Shut down MacBook, waited a few seconds
• Started MacBook again, connected the LG monitor, problem manifested within 5 minutes

had the problem with my ~15yr old EIZO via DVI and Thunderbold adapter to my 2022 iMac. Tried everything, failed gloriously. Luckily enough we hadan non-used DELL display in our office that i connected via Display Port to Mini Display Port and – hallelujah! – it works!

Another vote for Apple fixing these issues.

Since upgrading to Sequoia 15.4 I started having display issues too. One of my 4k monitors (connected through a Thunderbolt 4 dock to my 14" MacBook Pro with an M1 Pro) can't be set to full resolution and is all blurry. The only workaround for now is to connect it directly to my mac, which kinda defeats the purpose of the dock.

This problem started for me today (April 2, 2025) after updating to Sequoia 15.4 overnight. I have two identical Sceptre C27 monitors, and the one I use as "Extended Display" goes black periodically with no warning. It stays black for a short while and returns, but now I don't trust it. I'm using a HDMI cable, Mac Mini M1, 16GN memory, wall-mounted monitor.

I've never had this problem before, and only the second monitor seems to be affected. The first monitor is working normally. I tried adjusting the refresh rate (currently at 75 Hertz), but that doesn't solve the problem. I've also restarted the Mac several times with no fix. The current resolution for the working monitor is set at 1920 x 1080—going to a different resolution does NOT help. Changing the refresh rate does NOT help.

UPDATE: I swapped the cables on the monitors (Monitor 2 was plugged directly into the Mac mini, Monitor 1 into a Dock, and replicated the problem from Monitor 1 to Monitor 2. I'm starting to think the update broke my Display Port on my Mac Mini!

I have the same issue and I use an LG Ultra 4K connecting directly with a USB C cable (not using a dock).