Has anyone else updated a MacMini m1 to MacOS 11.3.1 and then had an 5K2 screen stop working where they're connected by Apple Thunderbolt cable? Screen is an LG 34" WK95U model (commonly called 5k2 as it's 5120 x 2160 pixels).
Mac mini 2018 or later
Hi there andrewkiwi,
We understand that you are having issues using your external monitor with your Mac. We’d be glad to assist.
To confirm, does this monitor work without issue with other devices or does something similar occur? Let’s also follow the steps outlined here to see if they help:
Get help with video issues on external displays connected to your Mac
If this continues after looking over that, please provide more details on exactly what’s happening and if you are getting an error message of some kind.
Cheers!
Hi,
Thanks - I didn't see your response so missed replying. Apologies for delay.
Monitor works fine with HDMI etc but only gets 5k2 resolution when using thunderbolt cable from M1 Mac mini to LG 34WK95-U directly. Worked fine until 11.4.1 at which point it simply refused to display a signal. The Mac mini system showed a thunderbolt device is connected and correctly identified as LG 5k monitor but no signal causing screen to operate. Removing other 4k screen made no difference. Having LG and Mac mini only with external keyboard and mouse still rendered no signal. After a few moments the LGH screen says no signal so goes to sleep. Currently have spent 3+ hrs on Apple support with senior tech. Have reinstalled OS and no improvement. Have erased and rebuilt Mac from scratch and now it works because 11.3.1 isn't built into 11.3. So in effect I've gone backwards (pre 11.3.1 install) and I'm simply not updating now until I'm assured it will work.
Normally (before this update) I was using 27" 4k dell with DisplayPort "display link" plugged into USB3 and LG via thunderbolt and 49" 4k Sony TV via HDMI. I do all my work remotely and it spans a lot of R&D so using a lot of sc been space and a lot of high res work.
5k2 screen no longer works on Mac mini M1 after updating BigSur 11.3.1
