OSX 10.15.4 colour problem on external monitors

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

Dear all, I have found some useful tips here but also many replies and questions from individuals not reading all the posts so in the end difficult to follow.

So let me summarize what worked for me.

No black magic !, no complicated scripts needed.

The issue came from the last update of MacOS and a bug linked to HDR being enabled for my 34WK95C monitor. In the OSD for picture mode I had choices for HDR settings that I had never seen before.

I went in monitor in preferences, unchecked the extend color range or HDR option and then I did a basic thing... I restarted my computer and the problem was solved. If you do no restart your LG monitor still is in HDR config so there is a mismatch...

So in the end a simple fix.

I just got the LG 27UK850 and the colors were just like people described in the other posts here. Very warm and reds were pink. I was able to fix this by going to System Preferences > Displays. This brought up two adjustment windows, one for my laptop, and one for my external monitor. I chose the external monitor window and selected the color tab. From there I chose a different color profile. The LG HDR 4K profile was what was selected by default. I clicked through the different profiles until I found one that I thought was appropriate.

I did not have to turn off HDR. The color profile was the only adjustment I made, and it looks great now.

Hope this helps!

The easiest solution for me was to switch to Displayport 1.2 in my monitor's settings. This disables the HDR option in Catalina's display settings and reverts the image back to normal.

The way to get back to normal colors is to activate and deactivate HDR several times, until the monitor does not think what's coming out of your Mac is HDR.

Apple has rolled out an update to address other issues today, but this is still unsolved.

Apple, I have that feeling you don't give a **** if I spent thousands on Apple products and that this might come with some expectations. That's fine. But then it should be a question of pride about your products to make sure problems like these - which make it look like cheap stuff - are solved as quickly as possible. IIRC, Microsoft solved this about three years ago. rant over.

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.

I had the same problem so I did a live chat with LG and this fixed/gave me a workaround: System Preferences > Display > on the LG monitor deselect "High Dynamic Range" and all will be good again.

I think I have fixed this problem by changing the setting in my LG monitors to use DisplayPort 1.2 rather than 1.4. This causes my Mac to remove the HDR checkbox from the Display preferences screen for each monitor. I'm pretty sure I would be constantly battling the Mac OS without doing this.

I'm running two LG 27UL650-W monitors.

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.

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!

MBP 16", macOS 10.15.4, LG 27UK850, USB-C connection

You might try the following, could help, it does for me, but as we've seen from this thread, it could be a hit or miss. I am using USB-C connection, I disabled DisplayPort completely and I have enabled Deep Sleep Mode from LG OSD. Now when you want to wake up your Mac you need to press the button on the LG monitor so it can wake up the monitor and send power to you Mac.

Might give it a shot, perhaps it makes a difference.