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Question: 10.13.1 --> scaling problem for external UHD monitor

After I installed 10.13.1 a week ago, I am having a problem for my LG UHD monitor (LG 27UD88-W).

Scaling function is not working.

Monitor works only for few options :

3840 x 2160 (low resolution)

1920 x 1080

1600 x 900 (low resolution)

1280 x 720


with 30 hz option only......

Before 10.13.1, my monitor was working fine with other options with 60hz.........this driving me nuts.

I tried to use switchresX, but it crashes whenever restart...

I did PRAM & SMC reset. Still not working properly....

any solution?????????

MacBook Pro TouchBar and Touch ID, macOS High Sierra (10.13.1), (Retina, 13-inch, Late 2016)

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Nov 25, 2017 10:48 AM in response to TWon2013 In response to TWon2013

(2016 MBP 13" w/ TB)

My problem was solved when I switched using the right side (UP) of USB-C port. Both of left sides didn't solve the problem.

I was using left side (up) USB-C before.

BTW, a link to the the port differences, below one : th/


LG monitor is for USB 3.1, not for thunderbolt 3.

Thus, it shouldn’t be a matter whether it is from left side or right side.

I currently have no problem with right side, but when I switch it to left, have a problem!!!!!!!

I hav no clue..... I still wanna go back to the left side due to my desk setting.

Any help?????

Nov 25, 2017 10:48 AM

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Dec 12, 2017 5:28 PM in response to eclise1 In response to eclise1

I am pretty sure it has sth to do with OS.

Right side is working, however, I still have a problem --> when restart, it freezes !!!!!!

Shut down & turn on again has no problem. Only problem with restart when it is connected to the UHD monitor.

This problem is still on going with 10.13.2.

APPLE please fix this!!!!!!!!!!!!!

Dec 12, 2017 5:28 PM

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User profile for user: TWon2013

Question: 10.13.1 --> scaling problem for external UHD monitor