macOS Sequoia 15.3 wont let me detect my second display

Same issue. Using my external monitor with MacBook Pro with no problems until the update. Issue started immediately after the 15.3 update. It takes me different steps when I come back to the office to get it to work. Sometimes power, sometimes unplugging cables, flipping the cable... today, it took all those steps numerous times before it finally recognized.

Got excited when I saw that 15.3.1 was released today - really hoped that there would be a fix for this VERY ANNOYING AND OBVIOUS software issue. But alas, my tunderbolt display is STILL not recognized.

Saw 15.3.1 appear last evening and IMMEDIATELY tried to put this on. I have tried many of the "solutions" even knowing it was DEFINITELY 15.3 that is the cause.

Unfortunately this version did not address this issue for me and it persists. Hoping Apple can get this fixed as it is simply annoying to have to cycle one monitor every time I sit at the machine after a break. Definitely ruins the experience they strive so hard to present!

Servant,

I am well aware of the technical specs on the M1 and have been for some time. I was aware that the specs purported to limit one to two displays, the iMac display and one external.

I researched the matter and discovered that despite that spec it was possible with a Satechi Thunderbolt DisplayLink docking station to run two external monitors. I bought the docking station and did in fact run three displays at once. This would seem to suggest that, at least when running Sonoma the M1 chip was up to the task, despite the specs you reference, of running three display monitors.

You appear knowledgeable; I would appreciate your insight. Why is it that an iMac M1 running the Sonoma OS was capable of generating three displays through a docking station, but the very same computer running the Sequoia OS cannot. I'm not a techie, but it seems logical that something changed and the only thing that changed was the OS. If Sonoma could provide three screens, why can't Sequoia?

Unless Apple wants to for some reason discourage use of docking stations.

Appreciate your time and your expertise.

Came across a clients 14" MacBook Pro (M3) that had this issue with a large (42" or so) curved LG Thunderbolt Display.

Followed most of the instructions below with no luck. Deleting the files mentioned below and restarting did not work as is.

What finally DID work was downloading the Display Menu app and using that to get the Mac to finally see/detected the monitor and allow me to extend the displays.

My recommendation:

Delete ~/Library/Preferences/ByHost/apple.windowserver.displays.<hex_string>.plist and reboot.

Download (App Store) the Display Menu app. Open the menu and it should detected your screen and allow you to extend (or mirror) your display.

Director of IT - major college at a large Big10 university

Same problem for me. I’ve tried all the fixes in this page and nothing has worked. It’s taken me 3hrs.

Thats 3hrs away from study for my final exam.

I’ve given up. Im going back to my study with the limitations of only one decent sized screen. So disappointing that Apple refused to allow us to work with more than one reasonable sized screen. Am convinced that this update & subsequent problems are all part of Apple’s need to make us do things their way.

Thanks for nothing Apple 🥺

I am having a similar issue since the 15.3 update and it is very frustrating to not be able to extend the displays in a reliable way any more. If I unconnected and connect eventually it will finally find it but it has been taking 20 minutes every morning to get his working. Do we have a timeline with this will be fixed. This is a horrible user experience.

Unfortunately, the delete the plist file did not work for me...really wish it had!

Since I had NO trouble prior to installing the update, I have no choice but to point at the update as the problem. I also wish there was an easy way to rollback updates that didn't require erasing everything my my Mac Mini M1 and reinstalling everything again...

I'm having the same issue as everyone else. I updated to Sequoia 15.4, and my second external display (a dell) only shows "Choose to Mirror or Extend Display from the menu". I can't make any changes to the display which is apparently unrecognized by the menu.

I've tried everything except delete the com.apple.windowserver file, because I can't find that file anywhere on my computer. It isn't in the /library/preferences/ folder or anywhere else. Am I missing something?

Everything worked before the update. Thanks.

RetiredLegalBeagle wrote:

I have the same issue. My desktop is a 2021 IMac M1. When operating Sonoma, I had two external Dell monitors working, in addition to the main display, through a DisplayLink Plug and Display Hub. One monitor worked with a thunderbolt to HDMI cable and one worked through a HDMI to HDMI cable. No problems. Worked like a charm. Download Sequoia yesterday and monitor on HDMI to HDMI is black. "No HDMI signal...." Called Apple; spoke to less than sympathetic tech who said my problem is with the DisplayLink folks. "But," I said, "there must be something in your new OS since it worked fine in your old OS. She said, "I'm sorry."

The iMac (24-inch, M1, 2021) supports a maximum of one external display.

iMac (24-inch, M1, 2021) - Technical Specifications - Apple Support

You connected two – at least one of which you connected in an unsupported fashion, using a workaround.

One drawback of using a workaround is that, if there is any change that breaks it, you must rely upon the third parties who supplied you with the workaround to fix things. Apple never promised that you could attach more displays than the Technical Specifications say that you can.

My guess would be that if you contact the company that manufactured the "DisplayLink Plug and Display Hub", they will point you at Synaptics. Whether Synaptics has new versions of their drivers that fix the problem yet, I don't know. But that's the site you will probably need to keep monitoring.

Synaptics – DisplayLink Graphics

DisplayLink Support – Troubleshooting: macOS

UPDATE: This fixed my problem!!!

RonKabele wrote:

I believe that is the case for the M1 Mac Mini, perhaps one of the laptops. The Mac Studio M1 I have supports three monitors because that’s what I’ve been doing for over two years. But I do have a Kensington TB3 dock where two of my monitors are plugged into. I would also guess the first M1 Mac Pros support at least three or more monitors.

The M1 Mac mini supports two monitors - one connected via USB-C or Thunderbolt, one connected via HDMI.

The M1 Max and M1 Ultra Mac Studios support up to five monitors.

There were no M1-series Mac Pro desktops.

With regards to MacBook Pro notebooks,

• 13" MacBook Pros with plain M1 chips support only one external monitor.
• 14" and 16" MacBook Pros with M1 Pro chips support up to two external monitors
• 14" and 16" MacBook Pros with M1 Max chips support up to four external monitors

not working for me :(

This does not work for everybody. Even if it did, it *clearly* indicates some kind of OS issue.