macOS Sierra no longer supports ultrawide monitors?

that's the model I used to have. I was eventually able to get rid of it by completely uninstalling two apps: Duet Display for Mac and ScreenResX. I have a different model now so unfortunately I can't say if those programs ever fixed the issue with an update, but if you use either one, I'd try uninstalling.

I just did something similar. I have a LG Ultrawide (2560 x 1080) monitor and just got a 2017 MacBook Pro (with 4 USB C ports). My old 2014 MacBook Pro was able to drive it via a Thunderbolt 2 to DisplayPort cable.

I bought a USB C to DisplayPort cable to connect new MBP to the monitor. It didn't work. Display Preferences would set the resolution to "1080p" which was stretched and ugly. SwitchResX didn't help either.

But I had a USB C to HDMI connector and a spare HDMI to HDMI cable. This did work. I got the full native resolution of the monitor without having to touch any settings.

I'm running 10.13.3 FWIW.

I had the same problem. Simply solved by replacing the mini Display to HDMI by a mini Display to Display cable. Cost less then 10 euro. Works for me under Sierra & High Sierra.

"I switched from HDMI to DP using this cable ($9)."

The cable you selected is a 4K ultra HD cable.

I was only using an HD 1080P cable.

I wonder if the 1080P cable is a problem with these extra pixels and the ultra wide monitors.

I have a Mac Pro 4,1 (2009) with ATI Radeon HD 4870 512 MB upgrade graphics card.

The ATI Radeon HD 4870 512 MB has a D-DVI and a mini display port output.

I have the LG 34UM69G-B ultra wide monitor with its HDMI, Display Port, and USB-C inputs.

I tried various cable connections that did not work to give me full resolution.

1) Cable 1: Single DVI Cable; with Apple DVI to HDMI adapter. (Barely Functional-wrong resolution)

2) Cable 2: Mini Display Port to HDMI adapter; with HDMI Cable. (Monitor never recognized - sleep mode only).

3) Cable 3: Mini Display Port to HDMI 1080P cable. (Monitor never recognized - sleep mode only).

4) Cable 4: Mini Display Port to Display Port 4K cable. (Monitor Recognized and full resolution).

I thought my graphics card was going to be the problem and it was not.

It is the cable selection that was my issue.

I am not running Sierra or High Sierra yet.

Still running OS X El Capitan 10.11.6.

If you have not yet tried Cable 4 above, I would suggest you do.

I opted for the 4K cable just in case because the number of pixels we are pushing are higher than standard HD.

I had luck with "Cable Matters Mini DisplayPort (Thunderbolt™ 2 Port Compatible) to DisplayPort Cable in White 6 Feet - 4K Resolution Ready".

There is no audio transfer between the card and the monitor. I was not expecting it.

I just wanted to document how I achieved a working monitor in case it might help others in the future.

Good luck.

You MBP 2012 was subject to a free repair/recall.

MacBook Pro Repair Extension Program for Video Issues - Apple Support

You have an NVIDEA graphics controller chip.

NVIDEA has their own drivers you can try to download and use instead.

You also may have a built in graphics controller as part of the processor for lower power.

Have you tried that option instead of using the NVIDEA graphics controller chip.

Also have this issue, not just for widescreen displays but any display I use HDMI to connect with does not utilize full screen real-estate. I was able to fix this issue for some 27" Dell monitors at my work by using a VGA cord with a VGA to thunder-bolt dongle.

After this and other software related issues, I've decided I'm done trying to dance around apple's issues that don't get fixed and the only solution is to buy more apple products.

As a software developer this is really disappointing but if Apple can't provide basic functionality like connecting to a monitor and configuring the correct resolution then there is no point investing more time and resources for more work around solutions.

I have the same issue with OSX Sierra running on both iMac 27" 2010 & Macbook pro retina 2015 when using Hitachi 50" U4k 50HK6T74U. When I plug my Dell laptop in with Windows 10 the full resolution capabilities are accessible which makes Apples position with generic U4K modes not being supported a puzzling one. No fixes that I have come across yet either

I've been using an Asus PB298Q for the past 2 years with a mid 2012 MBP and rather frustratingly with a recent MacOS update it stopped working (see thread on Mac crashes when I plug in display 10.13.3).

I've been told to downgrade but as I had not used the monitor for a month or so I can't be sure when Apple broke compatibility. The HDMI input suggests the wrong resolutions and the DisplayPort input crashes the Mac.

Any insights from anybody else here?

Don't always put the blame on Apple; there are a lot of monitors out there that simply report incorrect EDID data, and Apple only supports the resolutions it is told by the hardware it supports.

Sometimes when that goes awry it's Apple's fault, sometimes monitor manufacturers. It's a really weird situation.

I am seeing the 2560 x 1080 option with my just new LG LM 34um69G-B, ultra wide HD (1080p) monitor.

However, when this resolution and others are selected by scaling down, the screen is not very readable.

I am using Mac OS X El Capitan 10.11.6 on a Early 2009 Mac Pro (4,1).

My video card is an original Mac upgrade card, ATI Radeon HD 4870 512 MB.

I am presently using D-DVI link cable with the Apple DVI to HDMI adapter to the HDMI input.

I suspect something is wrong with the cable and/or the card that it is not capable.

I initially tried a mini DP to HDMI cable and the monitor was not even recognized on startup.

Can you please tell me what graphic cards people are using and what cables/adapters your are using to get the Mac Pro to drive the LG ultrawide monitors?

Thank you in advance.

I have just bought a LG 34UM61-P monitor only because it had the screen split function. I tried to use with my MacBook running Sierra OS 10.12.6 and to my disappointment this LG feature does not work on the monitor.

Does anyone have an update if Apple have fixed this problem or is their a simple and easy fix for this problem...?

Thank you..!

Oh wow... Apple have not mentioned that to me. Let me raise that with them.

They did fix a HDD cable issue but I had to pay for that as it was only covered for 4 years (and only £30 anyway!).

Also my video card is Intel HD Graphics 4000 so no nvidia driver for me. Thanks though.

Hi,

i'm having the same problem but with my LG 25" ultra wide. Im trying the SwitchResX route, but not having much joy.

You got it to work ok then?

But the um68 was much better?

Thanks

Hi,

i'm having the same problem but with my LG 25" ultra wide. Im trying the SwitchResX route, but not having much joy.

You got it to work ok then?

But the um68 was much better?

Thanks