Big Sur 11.4 update, no connection to LG 43" external monitor screen

[katewes]

I'm so silly. The LG 43" screen was working nicely with my Mac Mini M1 16GB under Big Sur 11.1 -- and then, reading the forum comments about how the problems with external monitors had been solved, I upgraded from 11.1 to 11.4, and now there is no image on the screen. And what's more, it's a really busy period, and I don't have time to go down to the Apple Store to get it fixed. Expletives.

For people who've gone through this, are there any obvious steps I can take?

 

[Altis]

Haven't gone through it, but is there a way to try a different means of connecting the monitor? Perhaps adapt it another way.

Quite sad that such fundamental functions aren't sorted by Apple...

 

[GJtn7]

First make sure all the cables behind the monitor are firmly inserted in place. Check the same with the cables on the Mini.

Does the LG monitor show a power light? A standby power light? Any message like no display detected on the blank screen when the monitor is turned on?

If using a USB-C to DisplayPort cable or USB-C hub, try a direct HDMI to HDMI connection. A HDMI cable from the Mini’s HDMI output to a HDMI input on the LG monitor instead. Make sure the HDMI cable you have is suitable for 4K.

Have you tried to unplug the display cable and reconnect it while the Mac and monitor is on? That may wake the display.

Does the monitor work when plugged into other computers or devices?

Connect the Mini to your TV to see if you get a display output on your TV.

 

[katewes]

First make sure all the cables behind the monitor are firmly inserted in place. Check the same with the cables on the Mini.

Does the LG monitor show a power light? A standby power light? Any message like no display detected on the blank screen when the monitor is turned on?

If using a USB-C to DisplayPort cable or USB-C hub, try a direct HDMI to HDMI connection. A HDMI cable from the Mini’s HDMI output to a HDMI input on the LG monitor instead. Make sure the HDMI cable you have is suitable for 4K.

Have you tried to unplug the display cable and reconnect it while the Mac and monitor is on? That may wake the display.

Does the monitor work when plugged into other computers or devices?

Connect the Mini to your TV to see if you get a display output on your TV.

I've been with Apple helpline for over an 1 hour.

Tried everything.

Conneted the Mac Mini to two different monitors.

Unplugged, replugged cables, reversed the cables, tried different HDMI cables.

I was always using HDMI, not USB-C for connecting the monitors.

The problem happened the instant after rebooting after upgrading from 11.1 to 11.4

Apple are sending out a technician under AppleCare+

 

[senttoschool]

There were reports of 11.2 having more external monitor issues than 11.1. I guess 11.4 didn't fix those issues.

 

[gusping]

I'm so silly. The LG 43" screen was working nicely with my Mac Mini M1 16GB under Big Sur 11.1 -- and then, reading the forum comments about how the problems with external monitors had been solved, I upgraded from 11.1 to 11.4, and now there is no image on the screen. And what's more, it's a really busy period, and I don't have time to go down to the Apple Store to get it fixed. Expletives.

For people who've gone through this, are there any obvious steps I can take?

I recently upgraded my 2018 Mac mini from Catalina to Big Sur 11.3.1 and my 4K monitor broke (alongside other issues). Yet to try 11.4, but I'm not hopeful.... Big Sur is such a mess.

 

[katewes]

An update of the continuing saga.

Following the first time when updating too 11.4 bricked my Mac Mini, it had to be repaired due to the update causing damage to the firmware. After that, things were fine under 11.5

Then, I tried to update to 11.6, and it has bricked the Mac Mini M1 again. I'm in the process of pressing Apple for a replacement unit rather than getting it repaired.