macOS Sierra doesn't scale for 4k monitor

Question

I just upgraded to macOS Sierra. In El Capitan, I could have my 4k monitor (Dell P2715Q) scale so it was the equivalent of a 2560x1440 monitor, but in Sierra it only lets me do 2k/4k resolutions now.

Anyone know of a fix?

Solution

Immediately I thought to recommend enabling HiDPI mode, which basically allows you to change the display to use half of the real pixel density without changing the resolution:

sudo defaults write /Library/Preferences/com.apple.windowserver.plist DisplayResolutionEnabled -bool true

but then I did the math and realized that you want 2/3 of your full resolution, not half.

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯

^ This feature does not seem to be applicable in macOS Sierra anymore.

Third party apps such as 'QuickRes' and 'SwitchResX' don't resolve the issue. They only see the same resolutions that macOS sees.

For what it's worth, a reboot should fix it temporarily when you have your display plugged into your laptop. Once the screen sleeps though the issue returns.

Comments

[TomCat]

I'm having the exact same issue with the same monitor and opened a bug report (#2337029) using Feedback Assistant.

[Edward Jiang]

Awesome! Let's hope they fix it soon =] Is there any way we can upvote?

[batkuip]

Is this over HDMI? I had the same problem with HDMI - then switched to DP and it's all working fine.

[Edward Jiang]

This is over displayport.

[Admin]

I'm so glad other people are having this issue. I use 2 of these same dell displays from a 13" retina and it's driving me nuts. I had one of them working at first but then it went away after about a half hour... enter image description here

[Chris]

Filed a bug report and referred your # @RichardHurt. My report # is 28405804

[juice]

I have a 4k monitor which on El Capitan gave me 5 preset options for resolution. If I boot up my Sierra laptop with the monitor connected to display port AND the lid on my laptop is OPEN, i get these 5 options. As soon as I close the lid the 4 option (from left to right) disappears.

[idmean]

Same issue with same monitor. Resetting the NVRAM also doesn’t fix the issue. Rebooting always does, until you close the lid.

[SuperTempel]

As a user who doesn't have this problem, would you please explain what the two screenshots are showing, exactly? I can't manage to guess it.

[Mike]

macOS Sierra Beta 2 should fix this problem. It fixed my resolution issue.

[juice]

As Mike stated the 10.12.1 beta fixes this issue

[wadda_wadda]

@EdwardJiang I recently ran into a similar problem wherein I have two of your monitors, one of which allows for scaling and the other doesn't. I managed to fix it by going into the monitor's settings and setting the DisplayPort mode to DisplayPort 1.2 instead of 1.1.

[Kevin Frei]

Can anyone confirm if this is indeed fixed in 10.12.1? It's what's keeping me from upgrading...

[Edward Jiang]

Yes, I'm running the 10.12.1 beta and it's fixed.

[Jacob]

I had the same thing happen in 10.12.3, and the only thing that worked was setting my display to DP 1.1 and then back to DP 1.2. Just selecting DP 1.2 (which was already selected) didn't work, not did any of the suggestions here, nor any amount of hard resetting. Not sure if this was a Sierra or display thing. The problem started after a crash where the MBP failed to wake from sleep, with the display connected.

[adib]

Experiencing this problem in High Sierra 10.13.2 (17C88) – what's the solution?

[Edward Jiang]

Hm, thanks! Yeah, putting the monitor at 1080p (as shown in my screenshot) still runs it in HiDPI mode -- just not sure why it's not scaling to any other intermediate sizes. Apple used to allow me to do this without a 3rd party tool, so I assumed this is a bug...

[egid]

I just ran into the same thing with the GM release. Took me by surprise - I'll be keeping an eye on switchresx compatibility.

[TomCat]

SwitchResX does allow me to configure the display as 2560x1440 but it is not HiDPi enabled. So, while the size is correct everything is a bit fuzzy. :(

[Henry]

I had to restart after running that command to get it work.

[Øle Bjarnstroem]

This command ( sudo defaults write /Library/Preferences/com.apple.windowserver.plist DisplayResolutionEnabled -bool true ) followed by a reboot worked for me.

[Giulio]

OSX 12.1 solves this issue