Can no longer detect 2nd display in MacOS Monterey

All of a sudden experiencing the same issue which has lead me to this thread. My macbook seems to definitely notice something is plugged in, because the mouse slows down when the monitor gets plugged in. What an absolute nightmare. Stuck working from home with covid and now can't even get my work done. Pulling out power cord is not working for me.

MacBook Air (M1, 2020) Running 12.4 Will not connect to LG 38**95C-W.

I suspect that there is something wrong with the Mac USB type C ports. This display works with a Ipad pro and same cables (its the only other device i have to test with)

Here is a recap of my experience with the M1 Air and USB devices quickly.

1. I Love the idea of having only one cable, so I make sure that a monitor would be able to use USB C. The first monitor I bought was a gaming monitor, and the monitor at first worked but then would not output sound. I reached out to Apple support and got the runaround - this was a less well-known brand, so I returned it. ** Major Issue with my customer support case here** My computer was brand new at this point also
2. I Bought an LG 34 in a monitor for a home office worked great - I bought a second for a remote Office again worked great, with no problems.
3. I Moved and left my old monitor at my old place for when I was there. I upgraded to the 38 In Curved- again, no issues for about six months, occasionally issues waking up the computer but nothing that I was concerned with. and then finally, No output. The monitor is detected when you plug in for a few seconds, but nothing shows up, and then the monitor displays no signal. Also, the top (closer to the monitor) thunderbolt will not even have a few seconds of recognition.

** The Thing that frustrates me is that now I am out of apple care warranty and suddenly having USB C issues again as I had with the very first monitor. And when talking to Apple support at that time, I was very adamant that I wanted to ensure nothing was wrong with the USB C port on my computer(I was coming off a couple of incredibly frustrating apple care situations, so I was overly cautious). They assured me it must have been the monitor, and they were kind of insinuating that not all companies make the best hardware, and I should not buy cheap products. Since it was a less well-known brand, I took their word at the time ( it was like scepter of something I can not remember - which worked great with a windows USB-C connection). Now I am out of warranty, and it is looking like I am not the only one with this issue. Apple support has been worthless once again - and it looks like I was probably correct way back when I first got the machine that something was wrong or at least "buggy" with their thunderbolt ports, but apple did not care then, and they don't seem to care now. O man, I miss the old days when you could walk into an apple store and be treated like a human RIP

I had the same issue and tried everything listed here. I even went to the Apple store and tried my computer out on their monitors. After a lot of searching, I found the problem. This does happen after upgrading to Monterey and it related to graphic card switching (at least for me on my 2019 Intel-based 16" MacBook Pro. To fix it, go to System Preferences - Battery - Power Adapter (left side)- then turn of "Automatic Graphics switching". I swear I was pricing new laptops when I stumbled on this. You're welcome

I picked up a new Mac Studio in March. It has no problem detecting my 3 brand new Samsung monitors but it can't remember the monitor set-up. After waking up from sleep, logging in and out of my photoshop login, and restarting, the Mac Studio persistently forgets which monitor is landscape, which is portrait, which monitor is the main display, and the arrangement (24" landscape on the left, 28.5" landscape in the center, 24" portrait on the right). It also loses the color profile and refresh rate. Sometimes it remembers settings for a few days but then it loses everything again and I have to begin the day by painstakingly restoring the set-up.

The situation did improve considerably when I installed Monterey 12.4, bought the new Apple keyboard, and activated touch ID. At the same time, I also rearranged the brand new USB-C cables from the monitors into the 2, 3 and 4 Thunderbolt slots on the back of the Mac Studio. I have found that I can "fix" the problem when it forgets the settings of the two external monitors by switching the USB-C cables from slot 2 to slot 4 and slot 4 to slot 2, putting the Mac to sleep, and then waking it again (hey presto, back to normal). However, the whole thing comes crashing down if I remove the main monitor cable from slot 3 (to use it as an external display for my MacBook). I do realize this makes no sense because the Mac Studio should be oblivious to the order in which the monitors are plugged in. However, IRL that doesn't seem to be the case. The Mac Studio wants the main monitor in the middle between the two external monitors.

I love this machine. I came up from a 2012 iMac so getting a Mac Studio is like moving from impulse drive to warp drive. Since I discovered the slot-switching trick I'm spending half an hour a week on the problem instead of half an hour a day. BUT it's still a real time sink and disruptor to workflow. I wish I understood why there is no "Save these settings" button in Display preferences.

I have a MacBook Pro (13-inch, 2019, Four Thunderbolt 3 ports). I have been using this laptop with 2 monitor for long time with no issues. I upgraded to the macOS 12.4 (21F79) build and ever since have a myriad of issues with the 2nd monitor. I will have to keep removing and adding the 2nd monitor for it to work. I sometimes have had to reboot the box. What is going on with the MAC OSX? What is Apple doing about this? When can we expect a fix?

I have a Mac Studio. Before 12.4 I could use 2 HDMI monotor's without any issues. One through the HDMI output and one using a USB-C to HDMI dongle. The monitor using the USB-C HDMI dongles is no longer detected. Have tried everything in this thread but it will no longer work.

I had this same problem and solved it like this:

1. I normally connect to my second display with a USB C cable. It was this display that could not be detected.
2. I got an HDMI cable and with an adaptor connected it to my iPad.
3. Having a second display connected meant that when I was in System Preferences - Displays, holding down the option key resulted in the "Night Shift" button finally changing to "Detect Displays" and clicking this button resulted in the monitor connected with the USB C cable appearing.

Apple should update the OS so that "Detect Displays" is always available.

Very strange workaround (dell 32 usb-c):

1. turn off the monitor
2. open the laptop lid
3. turn on the monitor
4. close the lid

have to do the same thing every time MacBook is restarted. Very annoying.

Ive already planned to switch to Windows this fall, If this is not fixed. I am 39 years old and so just need a good productivity workflow. It seems Apple is playing dirty games to try to convince people to switch to Studio Display (I went to Apple store and guess what, it works fine on studio display). Coincidence?

No luck on 13 beta "Ventura." They should start naming these versions "Probably going to break some core piece of functionality."

The issue seems to be related to the hertz settings. Changing from variable rate to a static rate fixed the issue for me.

• Connect external monitor
• Go to settings
• Display
• Display settings
• select the external monitor
• change from variable herts to a fixed hertz, start with 30 and move all the way up to whatever your monitor supports.

This is horrible I can NO longer use my external monitors. PLEASE FIX THIS ISSUE NOW! And no, nothing works to troubleshoot this crisis.

The only way I can get my second monitor to work is:

• unplug my second monitor
• restart
• as soon as I select restart, plug in my second monitor
• it will work until my screen saver turns on and have to re-login

I have a 2019 27' iMac and for years I have had no issues with the 2nd display, but now it won't detect my 2nd monitor (LG 34'). This happened right after I upgraded to Monterey 12.4. I was hoping that 12.5 would resolve the issue but it hasn't. I've tried all the 'fixes' on this forum and nothing works. This issue has severely impacted my job performance. Please advise!

I’ve reinstalled Monterey and this solved my issue! just a reminder: you can reinstall macos without losing your data, from the cmd+r menu. https://support.apple.com/en-gb/guide/mac-help/mchlp1599/mac

Hello all,

I had the same issue and could not figure it out for a while. By trial and error was able to resolve it. Here is what I found. I have one screen connected through usb c directly, another one was connected through a dongle that had hdmi connection and it was not working. The problem for me as I learned was that I had another dongle connected for usb devices, like external hard drive and keyboard. It has an hdmi port, BUT I had nothing connected to it. It still created an issue. As soon as I connected a dongle without any hdmi ports, everything started working properly. Both screens work now. Hopefully this can be helpful to someone else.
Posted 4 months ago by  sauser33

This worked for me! I had an extra dongle with an HDMI port and after I disconnected this dongle (and all others), I was able to connect the DVI-D to USB-C dongle to my 24in Cinema Display. For anyone needing to know my systems specs: iMac (24-inch, M1, 2021), Monterey (the devil's OS) 12.5, connecting a 24in Cinema Display connected with a Club USB3.2 Gen1 Type-C to Dual Link DVI-D (HDCP OFF) dongle. Thanks again to sauser33!!!