MacBook Air M1 - Washed out Dell External Monitor (Ypbpr Mode)

Also posted on Whirlpool, with acknowledgement but no pathway ahead yet. hoping the early adopters of M1 on here have found a solution.

A new Mac user after 30 years of PC. Moved for M1 n the cyber Monday 10% off deal. So far so good.

USB C to HDMI (various adapters) puts my Dell U2913WM into a washed out mode, compared to the same monitor on the MS Surface Pro. Research says this is a known issue for a decade now of Mac outputting analogue YPbPr mode instead of digital RGB to the Dell.

Found this blog that addresses a rather painful manual fix to the problem:

It doesn't work on M1 Macs. there are some workarounds posted, but on my Mac the script stops before it creates he needed file… I get the message "Is there a second screen connected" and "Can't detect external screen". this means the config style file needed to be edited to RGB isn't there.

This ability to change the screen mechanism from YPbPr mode to RGB seems so trivial and unexpected to be such a PITA in the glorified (and so far mostly true) Mac experience. Coming from a high proficiency windows user.

Any advice. Driving me insane doing video conferencing with ghoulish looking people. (Less colours means less sharp and less skin tones)


  • +2 votes

    Are you sure it isn't trying to treat it as a retina display, putting four pixels where one normally used to be or the other way around? Can you take a photo of what it looks like, the screen with the Mac connected that makes people look like ghouls.


    It seems a pretty well known issue. YPbPr is analogue for DVD players on HDMI to screens.

    The irony is I have taken photos to compare and my Samsung AI makes the faces look better so you can't really see the effect (crying face).

    The technical difference is 16 to 235 colour scale in analogue and 0 to 255 colour scale in digital RGB.

    Here is the setting view.
    On the Intel based surface pro it defaults to RGB input mode

    On USB C to HDMI with high quality cable.
    Connecting the M1 to a Philips display [email protected] gives default RGB digital mode and good colour


    Try a USB-C to DisplayPort adapter?


    I've ran into issues with Dell screens and Macs a few times now (2K monitor would only display as 1080p)

    Not sure if you read into the comments on that script, but it looks like M1 Mac's don't use the CoreDisplay kext/API that Intels do. That script uses CoreDisplay to detect monitors and generate the patched EDID file. Which is why you are getting that error.

    This guy had luck getting RGB with a certain hub but was limited to 30Hz (4k)