Washed out external monitor on M1 Mac mini on usb c

I've exactly the same issue with my Mac mini 2018 (Macmini8,1) running macOS Big Sur 11.2.1: External display has washed out colors when using USB-C to DisplayPort cable !!

I bought two USB-C to DisplayPort cables and the result is always the same: washed out colors.

The same monitor with an HDMI cable works perfectly. I've also tried an USB-C to HDMI adaptor with an HDMI cable and it also works perfectly. This makes me believe that the issue is really related to the DisplayPort.

Macmini8,1 with Intel UHD Graphics 630 to iiyama ProLite XUB2595WSU:

• HDMI cable: no issue
• USB-C to HDMI adaptor + HDMI cable: no issue
• USB-C to DisplayPort cable: washed out colors

I don't have washed out colors when I plug my Windows laptop into the same monitor using the USB-C to DisplayPort cable !! The monitor and the cable are therefore not the root cause of the issue.

We are not the only ones to have the issue:

• External display attached to MacBook Pro has washed out colours
• Fixing the External Monitor Color Problem with My 2018 MacBook Pro
• External Monitor Color Space, Part 2: Big Sur

Regards,

Xavier Mawet

I have the same issue. LG 27UD88 Ultra HD USB-C display looks washed with an M1 Mac. I think it sends a "limited range RGB" (16-235 brightness levels) signal instead of full range RGB (0-255 brightness levels) which makes blacks gray and whites dull.

Same display with the same USB-C cable works perfectly with an Intel Macbook and Intel Mac mini.

Since this is an USB-C display (charges through the same connection), using HDMI is not an option. It is really unheard that limited RGB would be sent over DisplayPort (this is usually an option in case of HDMI) so the display has no option to compensate for this.

It is very sad that even after almost half a year Apple can't iron out these GPU driver issues. An other annoying bug is that M1 macbooks don't support DDC/CI protocol which renders apps designed to change the native brightness of the display (like MonitorControl or Lunar) inoperable on M1 macs. This is a huge setback for many of us.

Apple please FIX THIS already!!!

Found some solutions. I've had the exact same problem. I have a M1 Mac Mini using 35-inch LG monitor via USB-C to Display Port. Prior to 11.3, turning off the monitor then back on again used to fix it and the colors would no longer be washed out. After upgrading to 11.3 I initially had no problems with the color, but I started fiddling around with the HDR settings (in System Preferences -> Display) - big mistake - _don't_ check the HDR tick box. I ended up checking the HDR tick box and the colors became washed out again, even after unchecking the box. I tried turning off/on the monitor, unplugging the monitor, rebooting, changing out to a USB-C to HDMI cable then back to USB-C to Display Port - but none of these worked - still washed out colors. The solution I found was to mirror my display via AirPlay Display (in System Preferences -> Display) to my Samsung TV, then turn off the AirPlay Display, and my monitor reset back to the nice dark/vivid colors and no longer washed out. That worked for me, hope that helps :)

Hello, David Oldenburg!

Thanks for reaching out in Apple Support Communities! From your post, it sounds like you're having trouble with the video on your external monitor when connected to your Mac. We'd like to help out!

Does this happen when you use a different USB-C cable or when the same monitor is connected via HDMI?

If so, we recommend using the troubleshooting steps to help with video related issues as described in the support article below:

Get help with video issues on external displays connected to your Mac - Apple Support

"If you've tried these steps and your display still isn't working, contact Apple Support to get more help."

All the best.

I am in the same boat. L4 4K 27UK650-W. Using Caldigit USB-Pro with Macbook pro M1.

1. Display port - with or without the dock - washed out color. Tried what was suggested above. No luck. connects at 60Hz
2. HDMI - thru the dock - nice saturated proper colors. But, only connects @30Hz.

So, I am relegated to use HDMI @ 30Hz

2016 Intel Macbook - perfect colors @60Hz - Display port or HDMI. No Issues.

I worked with Caldigit and they confirmed that it is not their dock. They did spend a lot of time checking things out.

So, it took 5 years for Apple to mess something that was working. Disappointed.

You are doing it all wrong. :)))

This is the Apple way:

1. Connect to your external screen via Airplay
2. Change the mirroring setting in Arrangement (set your screen to mirror if currently unmirrored or the other way around)
3. Disconnect Airplay
4. Be amazed at the deep blacks and pure whites!

Hmm.. Maybe I should be more descriptive.

1. Macbook Pro M1 with LG 4K as external display on Display Port. Extended display mode.
2. Went to Display setting and changed Airplay Display setting from "Off" to go to My Apple TV. and used Mirrored mode.
3. THe display went to 1080p scaled mode. Colors stayed washed out
4. Disconnected from Airplay. Color stayed washed out mode. changed back to extended mode. COlor stayed washed out
5. closed the lid and opened back again.
6. Color stayed washed out.

Looks like I am missing something...

1. Connected to charger all along via my dock
2. HDR is turned off.
3. I can connect to HDMI with no change in cable or settings. Full colors, but 30Hz.
4. Yes. Big Sur 11.3
5. Cannot change the resolution before opening the lid as I have no KBD/mouse, using the macbook's own KBD/Trackpad
6. Cables are fine as my 2016 Intel Macbook pro in the same setup does full color & full 60Hz on both DP and HDMI. I can literally take one out, plug the other in the same setup, and voila. But, 2016 intel is very slow and with constant fan when I start zoom. My M1 is really fast.
7. I am not a big video editing guy, so I can live with 30Hz as long as I get nice colors

I think it is hit or miss. My Dell 4K monitor at work does DP with full colors @60hz with no issues with this M1. It is the M1 and LG 4K combo.

I experienced the same issue with a view sonic a Mini M1 and a Caldigit TB+ dock. (There is a solution, so keep reading!)

For a long time I used the HDMI output of the M1 mini and the DisplayPort output of the CalDigit to get a working setup. I found it very frustrating. Recently (after the 3rd update to bigger), I thought that this might have been fixed and tried again. With no luck. I changed the USB-C cable for good measure (same issue) and then started to google around. Sure enough lots of other folks had the same issue. Seemed to affect LG display. One message tipped me off though saying that the protocol over HDMI can use a dynamic range and that somehow this may be the cause of the issue. I decided to give it another shot and looked into the menu of the ViewSonic.

Sure enough there is, under "Color Adjust" a menu for "Color Format" that has

• Auto
• RGB (Full range)
• RGB (Limited range)
• YUV (Full range)
• YUV (Limited range)

And, low and behold, the display was set to "RGB (Full range)". On the hunch that the M1 was sending a limited range, I decide to switch to auto. And it instantly fixed the problem!

I am now running two 4K displays one hooked up via HDMI on the mini, the other via USB-C on the TB dock and everything works blissfully well.

I'm posting in the hope that it helps some of you. Go check the menu of your display and make sure that anything is color adjustment that refer to the "range" in RGB can do automatic or reduced.

Best of luck!

---

Laurent

Setting the display to Limited Range RGB is not a solution for the majority of the users, since

• most displays do not have the option for limited range RGB in case of DisplayPort connections (limited range RGB is mostly a HDMI thing, in the early days of digital transformation content was mostly encoded with this in mind due to technical considerations and even up to this day many SDR content is treated like this - but computer monitors should always use full RGB).
• Limited range RGB actually worsens the display quality (as it can reproduce less colors) even if the dynamic range is recovered by setting the display to "RGB (Limited range)".

This problem clearly lies in MacOS.

Hey,

there is a solution to this problem:

1. Install XCode from the app store
2. Go to /Library/Preferences in Finder
3. Click on com.apple.windowserver.display.plist
4. Under Root/DisplayAnyUserSets/Configs/Item X/Item X/LinkDescription change Range (this will define if the display output is limited RGB range or full - you want the latter so set it to 1) and PixelEncoding (this decides if encoding is RGB or YPBPR - you want the former so set it to 0).

After this you have to reconnect the display or reboot.

For more info take a look at this discussion:

https://forums.macrumors.com/threads/m1-mac-external-display-fuzzy-fonts-colors-ypbpr-vs-rgb.2276345/page-21

If you have a lot of Item-s you can try modifying all or just delete the preferences file and reboot.

Hope this helps!

Btw. the issue seems to be fixed or less prevalent in the latest Monterey betas.

I was able to fix this using the script located here: https://github.com/sudowork/fix_m1_rgb

Instructions:

• Open Terminal.app
• Run the following commands:

curl -o ~/Downloads/fix_m1_rgb.py https://raw.githubusercontent.com/sudowork/fix_m1_rgb/main/fix_m1_rgb.py

rm ~/Library/Preferences/ByHost/com.apple.windowserver.displays.*.plist

python3 ~/Downloads/fix_m1_rgb.py

• Reboot your machine and the issue should be fixed. On my monitors (LGUN83A) I noticed that the disabled "Black Level" setting was now correctly set to "High" on the USB-C, the same as the HDMI monitor.

I’ve had these issues since I bought my Mac mini back in Dec 2020 and have now SOLVED the issue. If you enable HDR this eliminates all flickering, shimmering, horizontal lines etc on my displays. I’ve tested this by switching HDR off when watching a video and the shimmering etc returns.. See screenshot for my settings. Hope this helps anyone. Ffor info, I have an M1 Mac mini 8gb and 512gb ssd running macOS Monterey 😁