Some macOS Big Sur users running update 11.1 and recently released 11.2 have experienced ongoing issues with external displays, based on various reports in the MacRumors forum, Apple support communities, Twitter and Reddit.
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There are at least two separate issues at play, but both are related to external display connections. It seems that the issues have started with update macOS Big Sur 11.1 and update 11.2 has not provided any fixes and in some cases has made the problem worse.
The first problem is that USB-C ports do not recognize external monitors, which makes external displays unusable and unable to connect. This seems to affect DisplayPort and HDMI screens connected directly and via hubs and adapters.
Warning: The Big Sur 11.2 update is breaking USB-C ports for many. I lost the second monitor and now I can only use HDMI. Apple support had no solution, so I guess I will wait for 11.3 to fix the 11.2 update which would supposedly fix external monitor issues. @Poma @Virgin @AppleSupport
– Jason Sedlaczek (@jasonsed) February 3, 2021
We saw this issue first hand after upgrading a MacBook Pro to macOS Big Sur 11.2, with the update preventing the connection of an external monitor with USB-C and there are several complaints from affected users. From Reddit:
Upgrading to 11.2 broke my second external monitor connection.
LG Ultrafine 4k main monitor (Mac version) connected via Thunderbolt.
The secondary monitor (same model) connected via an HDMI-> DisplayPort adapter (BENFEI) and then the DisplayPort-> USB-C cable no longer works after the update (worked fine in 11.1 before updating -lo).
It looks like macOS recognizes the monitor and resolution, as shown in the display settings, and Apple Support has been able to remove my computer and view both screens. It is almost as if the signal is not sent for the monitor to turn on.
The second issue translates into resolution issues with external displays that cannot run at a full 4K 60Hz resolution, instead of crashing at 30Hz. In some cases, a 4K monitor is only recognized as a 1080p monitor.
MacOS Big Sur 11.2 does not solve the problem I have with the MacBook Pro M1, where my external monitor is locked at 30Hz despite being capable of 60Hz 😞. – Patrick O’Rourke (@Patrick_ORourke) February 2, 2021
It seems that many of those affected with screen issues have a 16-inch MacBook Pro, but there are also reports of other Macs with the same connectivity issues. There seems to be no reliable, widespread and proven solution or solution at this time.
Mac users didn’t experience these issues in the initial version of macOS Big Sur 11.0.1, and it looks like the macOS Big Sur 11.3 update released yesterday doesn’t fix the issue either, but there’s still time for Apple to work on a fix before the 11.3 software sees a public version.