Monterey 12.0.1. Second Monitor Issue

I found the solution:

1. Plugged in the dongle with the HDMI connection to the LED screen (2nd monitor)
2. Turned on monitor
3. Went to System Preferences
4. Picked 'Displays' (different screen from hitting displays when monitor is not connected)
5. Hit 'Display Settings'
6. Changed the resolution to 720p
7. Changed the refresh rate to 60hz

All - Frustrated by the same issue we've all been facing with the 12.1 OS upgrade eliminating my ability for my MacBook Pro to connect to my 32" Samsung external monitor.... I tried every combination of everything. Different mac, HDMI cable, monitor, adaptors, etc... as we all have. Finally... in frustration I took a chance and overnighted in a DisplayPort to USBC cable from Amazon. Not all of you may have a DisplayPort on your monitor... BUT... I plugged it in and it worked just fine! SO happy.

SO... maybe the issue Apple has with 12.1 has to do with HDMI port connection via ANY means! Worth a try for you! Cables are cheap, and I ordered the "USB C to DisplayPort Cable for Home Office (4K@60Hz, 2K@165Hz), uni Sturdy Aluminum DisplayPort to USB C Cable [Thunderbolt 3 Compatible] for MacBook Pro, MacBook Air/iPad Pro 2020/2018, XPS 15/13" for $13.59! No dongle needed.

I've had this same issue since an Apple computer tech fixed my 6 month old iMac under warranty and decided to upgrade to Monterey for me. As soon as I tried to connect my second monitor - nothing. I read all the responses here, tried everything, tried an older monitor from work as well. Logged a support ticket through Apple and no luck at all - was just told to restore to Big Sur which I didn't want to do because that would take another 24 hours to restore all my data.

I took a gamble and ordered a USB Display Adaptor from Amazon:

https://www.amazon.com.au/gp/product/B09B9Q4637/ref=ppx_yo_dt_b_asin_title_o01_s01?ie=UTF8&psc=1

Plugged my HDMI cable into the adaptor and IT WORKS!!! I downloaded the driver as recommended by the product and no issues at all. No flickering, nothing. I'm now back up and running! I cannot believe that this fixed it! The adaptor was ~$80 but so worth it! I feel complete again :) I hope this helps someone else having the same issues. I've got a 2021 iMac and have a 12 month old Lenovo monitor connected.

I had the same issue. I just upgraded to monterey 2 days ago and here's how I fixed it.

What I was using:

2 vga to displayport cables with displayport to usbc adapters on the end, and 1 vga to hdmi.

The 2 displayport ones went directly into the mac and the hdmi goes into the usb hub thing (which provides power and everything too).

What works:

2 vga to hdmi cables plugged into separate hdmi to usbc adapters similar to the apple one. The one plugged into the apple adapter stayed the same.

(Very similar to these is what I have now https://www.amazon.com/dp/B07S8MKJ6Q/ref=cm_sw_em_r_mt_dp_dl_68Q38D22TS2Q84WKJN7A?_encoding=UTF8&psc=1 )

My best guess is that the displayport to usbc wasn't "liked" by the system due to them removing certain usb drivers.

So about $80 I was able to get everything working again. On the plus side I have a billion usb ports now.

I created this account specifically so I could share and that hopefully other people can learn from my experience.

Update: I can confirm that using VGA > USB-C cable + Apple USB-C to VGA Multiport Adapter, a second monitor works (12.1). The issue seems to be HDMI. It feels pretty good to have the second monitor up and running and not relying on an iPad.

Hi all, I borrowed a VGA-USB-C adapter from a colleague of mine, which brand is not Apple (it is Conceptronic) and the external monitor works perfectly. So, the problem is with the official Apple VGA-USB-C adapter, which makes that the external monitor doesn't work. So, it is quite paradoxical. We spent a lot of money on Apple Adapters and they didn't work!! Please, Apple, this problem should be easy to fixed: Fix the issue and make that the Apple VGA-USB-C adapters work in our MacBooks!

I had this at first. I use a USBC/Thunderbolt Hub from OWC (Other World Computing). I noted that under System Preferences>Displays the external display no longer showed up.

I powered down my iMac and 21 "Cinema Display and unplugged them. I disconnected all cables from my USB-C/Thunderbolt Hub and disconnected its power source, as well. I restarted the iMac. I powered up the Hub and connected the cables. I powered up the the 21 " Cinema Display. Everything went back to normal . The display even showed up on System Preferences>Display, as before,.

Change your monitor's color profile setting

I have the same issue on Macbook Pro 2019 using an LG 27UN850-W Display, connecting with USB-C provided in the box. After updating to 12.1, I began experiencing display issues that I thought were related to the update. Anytime I would connect my monitor and try to scale the resolution to 4k, the monitor would shut off, the Macbook Pro 2019 would crash and leave me at login. And of course logging in just cycled everything again-- crash, shut-off monitor, display login...

After many trials, chats with Apple support, etc, I pretty much just gave up and started trying everything. AND FOR ME changing the color profile fixed the issue. I had loaded a custom color profile to try to match the color the closest possible to the Mac's display. Changing it to just the standard LG HDR 4K profile that came when I set up the display fixed all my issues.

So I had the same issue, I had just received the new Macbook Pro with an M1 chip. It worked fine on my monitor then I had to do a routine restart of the computer, when the computer turned back on it would no longer display on my external monitor (DELL). It was connected via USB-C which was also its charge source. I could get it to work using HDMI to HDMI but it wasn't great, I then managed to get it working HDMI to HDMI to my tv and that worked fine (obviously not ideal compared to my monitor). I then took the laptop to work and tried it on my work monitor (SAMSUNG) which had the same USB-C pass-through cable and no luck, again HDMI worked fine with this monitor.

I then tried switching from the USB-C cable that came with the monitor to a thunderbolt cable that my IT department supplied me with, and this WORKED! Since then it is still charging and displaying on my monitor through that one cable (Thunderbolt). I am yet to try on my monitor at home but I feel it will rectify it there too.

Really hope this will help some people as I know how frustrating this issue is!

I had the same issue (M1 pro, with LG 35WN75C-B over usb-c). Worked fine, until the last Monterey update (12.2.1). The solution that works for me is to remove the power cable from the monitor, wait 5 secs and put is back on. A bit frustrating that this seems the only way it works, but it works.

Kudos for this AskDifferent answer.

@Apple: please fix this!

I found a solution to a similar problem with my external displays after upgrading to Monterey. Hopefully this helps you too.

go to System Preferences >> Battery >> Battery and uncheck or recheck the “automatic graphics switching” option. Then restart your computer. Once I logged back in after restart, both of my external displays came back up again.

Hope this helps!

This issue still exists for me in 12.3 on an Intel (2018 T2) Mac Mini, verified as a Monterey regression. External monitors are kind of important on a Mac mini!

I always hang back on big upgrades for a few point releases as my environment is fairly complicated an early point release just burn time up doing Apple's testing for them. Issues seems to be quieting down so put my big boy pants on an upgraded to 12.3 from 11.6.5.

On 12.3 I can only have one monitor working in any boot cycle, first one wins and they just sit there flickering and failing to sync the second one every few seconds until I pull the power cord on the one that is failing to come up. Both identical Iiyama Pro-Lite XUB3493WQSU, both USB-c/Thunderbolt-3 connected (on different TB lanes on the Mac, and only 3440x1440x60/75Hz each monitor), no issues at all with anything from Mojave on until Monterey came along so definitely a software issue in this release.

Especially galling as the downgrade process is *so* broken in T2 Intel Macs. They won't downgrade restore the OS from TM backups, nothing worked for me until disowned it in Monterey and then nuked it back to its delivery era Mojave, but it still wouldn't forward upgrade from there other than to Catalina or (surprise surprise Monterey), seemed to have a total aversion to re-installing Big Sur. Completed in the end by making a USB bootable and lots of dead chicken waving. A day of my life lost and I'm still waiting for a migrate from my TM backups.

Anyway, things that didn't work that I've seen various people suggest:

• Moving one of the monitors to HDMI (made no difference).
• Power cycling in all sorts of orders.
• SMC and PRAM resets.
• Changing DP version level on monitors.
• Changing sync rates.

It is 100% repeatable, going back to any version other than Monterey resolves it. As a consequence I now have an extra Monterey volume that I can boot across to in order to reproduce the issue and would be more than happy to flush a few more hours working with someone from Apple to boot across and grab traces if it helps get some resolution, but I guess I'm going to be sticking on Big Sur for a while.

I gave up waiting for Apple to acknowledge the problem and put in some effort to fix it. This issue has deeply jilted my trust in Apple and resulted in my cancelling my intended device refresh. The problem seems to span all Macs supporting Monterey (devices old thru new). I hope Steve Jobs is 'turning in his grave' at Apple's moronic denial of this issue.

This past weekend I finally decided to blow away Monterey and fresh install Big Sur... what a pain, but at least I have my external monitor back in operation. I did notice that Apple released 12.4 today, but early indication is that there is still no fix for the external monitor issue. Let us know if you find different.

While searching regarding fixes in 12.4, I stumbled across this article on ways to work around the external monitor issue: https://machow2.com/external-display-issues/. Unfortunately it was too late for me to try the options I didn't previously try given I am back on Big Sur, but I thought I would share in case one of these 10 approaches helps others to find an acceptable workaround/resolution.

Uh, restarting with Option+R+P is fully documented by Apple Support, it will not harm your computer. Plus, it made my three monitors work again. https://support.apple.com/en-us/HT201255

macOS 12.2.1 appears to have fixed it! WOO HOO!!!!!!!