Catalina Beta 6 and 7 Killed my 4k external monitor

xwickx

macrumors newbie
Original poster
Sep 12, 2019
1
0
Dubai
Not sure if anyone else had this happen but after installing the latest build (10.15 Beta (19A546d)) - my 4K external monitor stopped working, it was working just fine prior to the installation. I have a MacBook 12" early 2015. I am using apple adapters, and have tried different monitors/TVs and different adapters. I have found that it works fine on: LG ultrawide monitor, 1080p TVs

but it doesn't detect the display for: LG 4K monitor, 4K TVs, and a Projector (not sure the resolution on that)

I tried "detect displays" from system preferences but it still doesn't work.

I updated with today's Beta release but still nothing. Is anyone else having this problem?
 

mmomega

macrumors 68040
Dec 30, 2009
3,389
1,543
DFW, TX
Not having the same issues.
I have 3 - 4K monitors on 3 different machines, all on catalina, all still working.
No adapters.
1 connected over USB-C on iMac Pro
1 connected over DP from eGPU on 2018 Mac Mini
Another connected over DP from eGPU on another 2018 Mac Mini

Hope you get it figured out.
 

EgbertAttrick

macrumors regular
Feb 25, 2008
218
41
Not sure if anyone else had this happen but after installing the latest build (10.15 Beta (19A546d)) - my 4K external monitor stopped working, it was working just fine prior to the installation. I have a MacBook 12" early 2015. I am using apple adapters, and have tried different monitors/TVs and different adapters. I have found that it works fine on: LG ultrawide monitor, 1080p TVs

but it doesn't detect the display for: LG 4K monitor, 4K TVs, and a Projector (not sure the resolution on that)

I tried "detect displays" from system preferences but it still doesn't work.

I updated with today's Beta release but still nothing. Is anyone else having this problem?
Similar, but not exact.

My MBP outputs to the display, but doe not detect it otherwise. I cannot put audio through my LG UltraFine 4k, and I cannot adjust the display brightness.
 

EgbertAttrick

macrumors regular
Feb 25, 2008
218
41
I solved the problem but powering down both the MBP and display, unplugged the display, and restarted everything. All is A-OK, now.