Users Report External Monitor Issues After Updating to macOS Monterey 12.3

Following the latest macOS Monterey 12.3 update, users are reporting several problems when using external monitors, ranging from Macs not detecting displays at all to inaccurate screen output, according to posts on the Apple Support and MacRumors forums.

24 inch imac and macbook monterey
In the ten days since the update became available to the public, users have already reported issues with the update bricking Macs that have had logic board replacements and problems with using game controllers. Adding to the list of issues, users are now reporting that the update is causing problems with external monitors.

According to users on the Apple Support and MacRumors forums, some external displays connected over USB-C are no longer detected by Macs after updating to the latest macOS update. As one user on Apple Support reports:

After updating my Mac mini today to 12.3, my monitor now no longer displays an image via USB-C, just keeps saying on no signal on the monitor.

I have tried HDMI and same issue. The odd occasion it will display a picture but once I shutdown or restart the mac mini it does not display a picture. The mac is booting up. I have had to resort to connecting it to my old TV with HDMI connection.

This is so frustrating.

Other users have shared similar experiences. While many also report issues with USB-C displays, others also say that HDMI connections to the Mac are not being recognized. Some users have been able to crowdsource potential workarounds in the meantime. According to one user on the MacRumors Forums, the issue stems from macOS not recognizing a DisplayPort protocol version, which meant they had to change the version to an earlier one with poorer quality output.

I've solved this problem (on 2022-03-15). On my monitor (LG LCD 27 27UN880-B IPS) I've went into settings, and I've lowered the DisplayPortVersion from the default v1.4 to v1.2. As soon as I've lowered the monitor's DisplayPortVersion, my Mac with OS X 12.3 has started recognizing the second display correctly. It seems that the new OS X update has issues with a DisplayPortVersion 1.4 protocol (has faster data rate, faster refresh, and stream compression). Hope this helps.

Another short-term fix floated on both the Apple Support and MacRumors forums is to unplug the external display for a short time, plug it back into the Mac, and then plug the display back into a power outlet, after which it should work. Some users have also reported problems when using two external monitors with their Mac.

The issue of only one external display being recognized when two are connected to a Mac seems to have been present throughout the beta testing period for macOS 12.3. Even after release, however, the issue remains. As one user on the Apple Support forums relates:

2018 Mac Book Pro 15" and I have 2 external monitors (same viewsonic model), have been using fine for just under 2 years. After updating to 12.3, one is recognized and one is not and I have no clue why. I have swapped cables, connected other devices, including a iPad Pro (all fine) I have tried all 4 ports on the machine no difference. The Mac book flashes when the unrecognized monitor is plugged in, but never displays an image. the monitor seems to think it's connected (I don't get the no signal warning) nothing.... 8* the monitor is powered and the screen it bright (bleed from the backlight). The other monitor (same exact model) connects and works fine.

The online reports suggest that these issues are not arising when using Apple's new Studio Display, but instead with third-party monitors, such as those offered by BenQ and LG.

macOS 12.3 is Monterey's largest point-update since launch, bringing with it Universal Control along with several other new feature additions. MacRumors earlier this week reached out to Apple for comment on the issues users are experiencing so far with the latest macOS update. We'll update this post if we receive a response.

Related Forum: macOS Monterey

Popular Stories

Apple Watch Ultra Night Mode Screen

Apple Watch Ultra 3 Launching Later This Year With Two Key Upgrades

Wednesday July 2, 2025 1:13 pm PDT by
The long wait for an Apple Watch Ultra 3 appears to be nearly over, and it is rumored to feature both satellite connectivity and 5G support. Apple Watch Ultra's existing Night Mode In his latest Power On newsletter, Bloomberg's Mark Gurman said that the Apple Watch Ultra 3 is on track to launch this year with "significant" new features, including satellite connectivity, which would let you...
iPhone 17 Pro in Hand Feature Lowgo

iPhone 17 Pro Max Battery Capacity Leaked

Thursday July 3, 2025 5:40 am PDT by
The iPhone 17 Pro Max will feature the biggest ever battery in an iPhone, according to the Weibo leaker known as "Instant Digital." In a new post, the leaker listed the battery capacities of the iPhone 11 Pro Max through to the iPhone 16 Pro Max, and added that the iPhone 17 Pro Max will feature a battery capacity of 5,000mAh: iPhone 11 Pro Max: 3,969mAh iPhone 12 Pro Max: 3,687mAh...
iPhone 17 Pro in Hand Feature Lowgo

iPhone 17 Pro Coming Soon With These 14 New Features

Friday July 4, 2025 1:05 pm PDT by
Apple's next-generation iPhone 17 Pro and iPhone 17 Pro Max are just over two months away, and there are plenty of rumors about the devices. Below, we recap key changes rumored for the iPhone 17 Pro models. Latest Rumors These rumors surfaced in June and July:Apple logo repositioned: Apple's logo may have a lower position on the back of the iPhone 17 Pro models, compared to previous...
iPhone 17 Pro Lower Logo Magsafe

iPhone 17 Pro's New MagSafe Design Revealed in Leaked Photo

Wednesday July 2, 2025 8:37 am PDT by
The upcoming iPhone 17 Pro and iPhone 17 Pro Max are rumored to have a slightly different MagSafe magnet layout compared to existing iPhone models, and a leaked photo has offered a closer look at the supposed new design. The leaker Majin Bu today shared a photo of alleged MagSafe magnet arrays for third-party iPhone 17 Pro cases. On existing iPhone models with MagSafe, the magnets form a...
airpods pro 2

AirPods Pro 3 to Help Maintain Apple's Place in Earbud Market Amid Increasing Low-Cost Competition

Thursday July 3, 2025 7:25 am PDT by
Apple's position as the dominant force in the global true wireless stereo (TWS) earbud market is expected to continue through 2025, according to Counterpoint Research. The forecast outlines a 3% year-over-year increase in global TWS unit shipments for 2025, signaling a transition from rapid growth to a more mature phase for the category. While Apple is set to remain the leading brand by...
Wi Fi WiFi General Feature

iOS 26 Adds a Useful New Wi-Fi Feature to Your iPhone

Wednesday July 2, 2025 6:36 am PDT by
iOS 26 and iPadOS 26 add a smaller yet useful Wi-Fi feature to iPhones and iPads. As spotted by Creative Strategies analyst Max Weinbach, sign-in details for captive Wi-Fi networks are now synced across iPhones and iPads running iOS 26 and iPadOS 26. For example, while Weinbach was staying at a Hilton hotel, his iPhone prompted him to fill in Wi-Fi details from his iPad that was already...
iOS 18

Apple Releases Second iOS 18.6 Public Beta

Tuesday July 1, 2025 10:19 am PDT by
Apple today seeded the second betas of upcoming iOS 18.6 and iPadOS 18.6 updates to public beta testers, with the betas coming just a day after Apple provided the betas to developers. Apple has also released a second beta of macOS Sequoia 15.6. Testers who have signed up for beta updates through Apple's beta site can download iOS 18.6 and iPadOS 18.6 from the Settings app on a compatible...

Top Rated Comments

UltimateSyn Avatar
43 months ago
Only Studio Displays are allowed from here on out. ;)
Score: 39 Votes (Like | Disagree)
kalsta Avatar
43 months ago
Because Apple makes both the hardware and the software, they are uniquely placed to offer this kind of user experience.
Score: 22 Votes (Like | Disagree)
TechRunner Avatar
43 months ago
I keep thinking I need to upgrade to Monterey, and Apple keeps giving me reasons not to.
Score: 18 Votes (Like | Disagree)
Freeangel1 Avatar
43 months ago
I might just go back to Big Sur. Monterey is like the Windows Vista.

Mac Studio owners are probably stuck on 12.3

Intel Macs can go back or even run 2 different versions of macOS.

Thats what scares me about the future of macOS on Apple Silicon.

You Cant Go Back. sort of like iPadOS.
Score: 16 Votes (Like | Disagree)
mxrider88 Avatar
43 months ago
New bugs, who would have thought..

My god macOS turned into an unpleasant mess.
Score: 15 Votes (Like | Disagree)
RedTheReader Avatar
43 months ago
More bugs on Monterey 12.3?!

Score: 10 Votes (Like | Disagree)