macOS Sequoia 15.3 wont let me detect my second display

Having a similar issue. After the update my m4 mac cannot recognize my LG c3 tv. My tv recognizes the mac (the hdmi port says "apple" for the hdmi detection) but mac cannot recognize the TV as a display. the "detect displays" trick did not work nor did deleting the plist

I have also tried multiple HDMI cables. Although - the cables i had been using worked fine until the update completed...

The best I can get is -- sometimes -- the monitor displays "choose to mirror or extend display from the [ ] menu. but the TV still does not appear as a display

this is very frustrating. i have tried plugging it in directly and via a dongle

I updated my M1 to 15.3 and it still works fine with the LG tv...

The “can’t run a portable display off the Mac, with one cable, and no separate power source for the display” thing involves a different issue (or set of issues( than what other people seem to be talking about in this thread.

Servant,

Thanks. It appears Apple does monitor these inquiries, as you appear to mimic the very thing I was told yesterday when I spoke with "Support."

I'm probably betraying my ignorance of such things, but it sounds as if Apple made some changes in the Sequoia OS preventing or inhibiting a further "work around", as you put it. A few suggestions: (1) rather than making "work arounds" required, you might try "work withs"; (2) an explanation of why the old OS worked and the new one does not might go further toward customer satisfaction and understanding than an attitude of what Apple did or did not promise; and (3) pointing the finger elsewhere is never a good strategy in seeking continued patronage.

As this site appears to attest, there are a lot of customers like myself who rely on multiple screens.. I would think the good folks at Apple would look for ways to accommodate those with this need in the design of their OS, rather than prevent it.

Thanks Servant.

Retired,

I don’t work for Apple.

The M1 iMac’s Technical Specifications were readily available before you bought it.

In addition, an examination of the Technical Specifications of all Macs that use plain M1 chips shows a consistent pattern. None of them support more than two displays, total, where the built-in displays on iMacs and on Mac notebooks count towards that limit.

If the plain M1 chip only has two display generators (as all evidence suggests), there is no macOS change that Apple could make to provide more first-class hardware-supported display outputs on Macs that use that chip.

That's all great. I have an M1 Pro MacBook and it had the problem. If you read this thread, you'll see that the majority of people posting have had a MacBook setup with multiple monitors on 15.2, and the setup worked. Your argument is about the nature of the bare-metal M1 CPU, and it is correct. It is also not relevant to this conversation, for obvious reasons: if people's MacBooks supported their monitors before with their CPU native abilities, they should continue to do so under 15.3.

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.

Has anyone found the fix yet? After connecting the macbook it just gives a black screen

I have a Macbook Pro M3 with MacOS 15.3.1

External monitor is LG LG 27UP650-W 4K HDR monitor

1. Tried a new HDMI to HDMI cable, did not work - infact the cable you get with the monitor is working with my other mac running on macOS 15.2 (INDICATING SOMETHING IS DEFINITELY WRONG WITH 15.3.1 update!!)
2. Tried switching from HDMI1 to HDMI2, still gives a black screen
3. Tried deleting .plist file from preferences and restart mac, still same issue (new file gets created as soon as I plug the HDMI cable in, but the result is still the black screen)
4. Tried unplugging EVERYTHING and PLUG IN again, still the same black screen

I am almost sure now its not a hardware issue - be it the cable, the monitor, or macbook HDMI port, because its working when I connect to a TV, this issue is only happening with the monitor

Everything works as expected when I connect it with my personal Macbook Pro with M1 Pro chip and MacOS 15.2

Please help :(

Retired,

If you want to continue talking about DisplayLink, I would suggest that you start a new thread. This thread is now four pages long, and if most of the people here are talking about issues with driving hardware-supported displays using native video output, they don't need the distraction of an ongoing subthread about DisplayLink.

Hello everyone. This solution worked for me. I panicked when after updating to Sequoia 15.3.1 my hub stopped being detected by mi Imac M1. I use the hub for the Ethernet cable, the SD cards, a couple of USB connections for external SSD from time to time, and my second screen which I almos depend on. Try this before deleting files!

Hello everyone. This solution worked for me. I panicked when after updating to Sequoia 15.3.1 my hub stopped being detected by my Imac M1. I use the hub for the Ethernet cable, the SD cards, a couple of USB connections for external SSD from time to time, and my second screen which I almos depend on. Try this before deleting files!

RetiredLegalBeagle wrote:

Servant

I apologize if I was rude. Thank you for your help.

I wasn't saying that you were being rude. I was suggesting that you start a new thread.

Your issue is different from that of others in this thread. Hardware-supported video and Displaylink-based video work in different ways. It is not clear whether a single Sequoia change is related to both issues – or if there were separate changes, one of which affected hardware-supported video, the other of which affected DisplayLink.

For the benefit of the people who are discussing issues with hardware-supported video in this thread, any further DisplayLink conversation should probably move to its own thread.

Thanks a lot, sangy987.

I was struggling with this issue ever since I upgraded to macOS Sequoia 15.1.

I'm now on Version 15.3.1 (24D70), and your solution worked perfectly for me.

My external display, the Samsung C49RG90, is now detected, and I can use the highest 5K (5120 x 1440) resolution.

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 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.

That solution worked for me. However, I do not believe you need to download anything. I didn’t. Since it’s a .plist, if you drag the file to your desktop and reboot, the operating system will create a new .plist file. You’ll need to go in and manually set your preferences again, though.