OSX 10.15.4 colour problem on external monitors

I need to correct myself – with HDR enabled in Display Preferences, the display switches to HDR and the colours are washed out and weird (like red is really a neon pink etc.), but with HDR disabled, the display switches to something (there is a popup in the right corner saying it's HDR) and the colours look totally different – like a 256 colours scheme. Both option are totally unusable. So in any case, there is a problem that started after I updated to 10.15.4 and I haven't found a reliable fix yet. Btw. I tried different connections (USB-C to Displayport, USB-C to USB-C, with a USB-C cable as well as Thunderbolt 3 cable) and the issue is there with each of these connections.

Can confirm this seems to also be an issue on the LG32UK550 - I've run the applescript mentioned in another comment and it seems to work sometimes. Seems to be random whether turning HDR off in the display preferences works or not. Recently upgraded to 10.15.6 and this issue started happening.

With HDR mode turned on colours are washed out and hazy looking (tried a few different HDR "modes" using the LG on screen display, but none of them are really workable)

Turning HDR mode off gives terrible colours (contrast is waaay to high, colours look neon as others have mentioned and text isn't nearly as smooth)

Toggling HDR on and off seems to eventually get me to a point where the monitor doesn't get locked into HDR mode and the screen is usable again, but this is hardly ideal as it happens anytime the monitor wakes up...

My set up is a 2018 Macbook Pro 15" running Catalina 10.15.6 connecting via TB3 to a CalDigit T3 Plus dock, then to LG monitor via DisplayPort (set to DP1.2 on the LG monitor)

Because it's a game of luck if my monitor works correct after sleep or reboot, I decided to get rid of HDR completely and fix it in RGB mode. So far I don't have any issues anymore.

1. Download the file patch-edid.rb from https://gist.github.com/adaugherity/7435890
2. put it on your Desktop
3. in the Terminal:

cd Desktop
rb patch-edid.rb

Now you will have a folder called "DisplayVendorID-..." (in my case it's DisplayVendorID-1e6d)

Reboot your Mac in recovery mode. If you have FileVault enabled, activate your Volumes with the disk utility now. Then switch to Terminal. Now type the following (make sure what you type matches the name of your Volume and the DisplayVendor folder):

Consider saving a copy of the folder in the second line below somewhere - i didn't need it.

cd /Volumes/OSX/System/Library/Displays/Contents/Resources/Overrides
cp -rf /Volumes/OSX/Users/username/Desktop/DisplayVendorID-1e6d .

Make sure not to miss the last dot. If it doesn't work, probably the path isn't entered correctly.

This will delete your monitor description and replace it with the one you generated.

Now reboot your Mac and enjoy a working display.

I'm looking forward to Apple ad LG to find a fix that allows to use HDR as intended.

The HDR box now appears in system preferences / displays. I'm fairly certain it wasn't showing up right after the update, so if you don't see it, try restarting, and unplugging/replugging things.

If the HDR box is checked, it limits the menu options available on the LG's built-in system. For me, unchecking this box and resetting the LG display seems to have returned things to normal.

This is in response to Orellana's last reply. The problem seems to be because of the HDR setting issue for the connected monitor.

This worked for my LG Monitor 27UK850/BK85U.

Go to System Preferences > Go to Display Settings for the connected monitor > Uncheck the High Dynamic Range Selection.

Refer attached screenshot.

Hope this helps.

Warm Regards,

Meenakshi

I had the same problem with my 2017 MBP 2.9 Quad i7, Radeo Pro 560 4GB with my LG 27UK850-W monitor. Running 10.15.4 (19E266). Colors were waaaay off, super neon and painful to look at.

Turned off the HDR setting and it's back to normal.

Thanks Orellana!

I have the same problem. I have LG 27UK850 and 2017 Macbook Pro 15. But even when I disable the new HDR option in Display preferences, the colours are still the same - the display still switches to HDR after waking up. Sometimes it's OK, sometimes not. I have to reconnect the display, but even then, it's like 50/50. I think it's a bug in MacOS 10.15.4 that still tells the display to wake up to HDR mode with all those crazy colours. I hope they'll fix it soon.

I also have trouble with colors on my LG 27UK850 (USB-C Thunderbolt) after upgrading to 10.15.4 on a Macbook Pro 15,3. The whites look gray and the reds are too hot. It's hard to look at. (Connecting an old Macbook Pro via displayport shows correct colors.)

Thoughts...

Color Profiiles: Has anyone had luck changing the color profile? I tried them all, and calibrating but none worked.

Firmware: I also tried to upgrade the firmware, as there is a recent update available from LG. However this command failed in the terminal. Has anyone successfully upgraded firmware as a fix.

HDR: I could not find any HDR controls as referenced in this thread available in MacOS system preferences. The LG's internal menu options are limited when using USB-C, and nothing worked.

Hope somebody finds a fix!

Firmware link for LG 27UK850:

https://www.lg.com/us/support/software-firmware-drivers?customerModelCode=27UK850-W&csSalesCode=27UK850-W.AUS&category=CT10000030&subcategory=CT10000033

I had the same problem. It took several restarts, but eventually the HDR option showed up and I was able to uncheck it, and it is back to normal. I disconnected my monitor from my MBP, reset the monitor to factory settings, unplugged/replugged, and restarted my MBP. The second time I restarted my MBP, the HDR option showed up for the monitor.

I have the very same problem after the update with an LG 27UK850.

Once I activate HDR, wait a few seconds a deactivate it again, the picture is back to normal. I also tried to calibrate in HDR mode with a colorimeter, but especially red tones still are way to bright and pinkish.

After sleep or reboot, the issue comes back, it seems that the display now detects an HDR signal from the eGPU (Rageon Vega 56 in my case), which is not there.

This is super annoying!

I can now either choose to waste energy by not letting the mac sleep or to spend half a minute on this issue ten times a day.

Turning HDR off solves the problem...BUT I DO want to use HDR on my LG 27UK850W on macOS. This needs to be fixed. Looks like the same problems Windows 10 hat 3 years ago with HDR. Anyhow does anyone know how to play HDR .mkv on macOS? VLC, IINA and Optimus Player all seem to look the same when playing 10 Bit HDR .mkv files.

My external monitor is an LG - 27UL600-W 27" IPS LED 4K UHD - same issue. I've turned HDR off, which will bring the picture back to normal.

When the laptop sleeps (shutting down signal to the monitor) and then is awoken, the monitor's colors can become over saturated. My only fix is to keep unplugging and replugging the monitor until the color saturation resets. This may take 3 or 5 attempts. Never happened prior to this past update.

Same problem as others have listed. 2019 MBP 15" and LG HDR monitor 27UL600. In HDR mode, colors are completely blown out (Red appear bright pink, for example). When I switch HDR off, the color is better, but not as crisp as pre 10.15.4 upgrade. Annoyingly if my MBP goes to sleep, when I wake it back up, the monitor color is off again (and seems that much harder to get it back to normal).

I have this problem too after updating to 10.15.4 (LG 27UK850). The workaround of disabling HDR from System Preferences works, but it is incredibly annoying that the problem comes back after the laptop wakes from sleep. Then HDR will be unchecked but colors will still be bad so you have to check the box, then uncheck it. Sometimes it doesn't work straight away so you have to do it multiple times and I found it's best to wait 10-20 seconds before you uncheck it to have a good chance.

Super annoying. At least give us the option to disable HDR permanently, Apple!

I have tuned off the HDR feature, but now my LG screens are super screwed up color-wise and I can't seem to fix it. Every time it goes to sleep or restarts there is a new adventure in awful color on the LG Screens. Again I have 2018 MacBook Pro and the Monitors are LG 34BK95U and LG 27UK850...Please please Apple Tech people take note of these issues and please fix ASAP.