Some macOS Big Sur users running the 11.1 update and the recently released 11.2 have encountered ongoing issues with external displays, based on several reports from MacRumors forum, Apple Support Communities, Twitter and Reddit.
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There are at least two separate issues in the game, but both are related to external display connections. The issues seem to have started with OSmacOS Big Sur 11.1 update, and update 11.2 did not provide a fix and in some cases aggravated the problem.
The first problem is that USB-C ports do not recognize external monitors, making external displays unusable and unable to connect. This seems to affect both DisplayPort and HDMI displays connected directly and through hubs and adapters.
Warning – the Big Sur 11.2 update breaks the USB-C ports for many. I lost my second monitor and can only use HDMI now. Apple support had no fix, so I think I’ll wait until 11.3 to fix the 11.2 update that was supposed to fix the external monitor issues … @Apple @verge @AppleSupport
– Jason Sedlaczek (@jasonsed) February 3, 2021
I saw this issue right after I upgraded 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 a few other complaints from affected users. From Reddit:
Switching to 11.2 broke the second connection of my external monitor.
LG Ultrafine 4k main monitor (Mac version) connected via Thunderbolt.
The secondary monitor (same model) connected via HDMI-> DisplayPort (BENFEI) adapter, then the DisplayPort-> USB-C cable no longer works after the update (it worked fine at 11.1 before the update).
MacOS seems to recognize the monitor and resolution, as shown in the display settings, and Apple support was able to remove my computer and see both screens. It is almost as if the monitor start signal is not sent.
The second number results in resolution issues with external displays unable to operate at full 4K 60Hz resolution, instead locked at 30Hz. In some cases, a 4K monitor is only recognized as a 1080p monitor.
AcMacOS Big Sur 11.2 does not solve the problem I face with MacBook Pro M1, where my external monitor is locked at 30Hz, despite the capacity of 60Hz 😞. – Patrick O’Rourke (@Patrick_ORourke) February 2, 2021
It seems that many of those affected by display issues have a 16-inch MacBook Pro, but there are reports of other Macs with the same connectivity issues. There does not seem to be a reliable solution or solution that is widespread and tested at this time.
Mac users did not encounter these issues in the initial release of macOS Big Sur 11.0.1 and it seems that the macOS Big Sur 11.3 update released yesterday also does not address the issue, but Apple still has some time to work on a fix before software 11.3 sees a public version.