macOS Sierra no longer supports ultrawide monitors?

Hi - This is an old thread, by I own a lat 2012 MBP and am ordering a couple of LG UltraWide 29UM58 monitors. Were you ever able to fix this issue?

Thanks!

I have a similar issue where the computer will not boot with an attached ultrawide monitor. The machine will boot if the monitor is turned off.

The LG-UM95-P runs via mini-DP to DP at 60Hz (see below). Audio from to this display cannot be changed by the apple OS-sierra.

Model Name: Mac Pro

Model Identifier: MacPro5,1

Processor Name: Quad-Core Intel Xeon

Processor Speed: 2.4 GHz

Number of Processors: 2

Total Number of Cores: 8

L2 Cache (per Core): 256 KB

L3 Cache (per Processor): 12 MB

Memory: 64 GB

Processor Interconnect Speed: 5.86 GT/s

Boot ROM Version: MP51.007F.B03

SMC Version (system): 1.39f11

SMC Version (processor tray): 1.39f11

Chipset Model: ATI Radeon HD 5770

Type: GPU

Bus: PCIe

Slot: Slot-1

PCIe Lane Width: x16

VRAM (Total): 1024 MB

Vendor: ATI (0x1002)

Device ID: 0x68b8

Revision ID: 0x0000

ROM Revision: 113-C0160C-180

EFI Driver Version: 01.00.436

Displays:

LG ULTRAWIDE:

Resolution: 3440 x 1440 @ 60 Hz

Pixel Depth: 32-Bit Color (ARGB8888)

Main Display: Yes

Mirror: Off

Online: Yes

Rotation: Supported

Automatically Adjust Brightness: No

Connection Type: DisplayPort

Television: Yes

DELL 1703FP:

Resolution: 1280 x 1024 @ 60 Hz

Pixel Depth: 32-Bit Color (ARGB8888)

Display Serial Number:

Mirror: Off

Online: Yes

Rotation: Supported

Adapter Type: Apple Mini DisplayPort To VGA Adapter

Automatically Adjust Brightness: No

Adapter Firmware Version: 1.03

While it is an oldish thread, it might be worthwile to mention...

I also had this problem with a newly purchased LG 29UM58-P, which has HDMI input only. Correct resolution only worked with SwitchResX.

So, I decided to exchange it for a 29UM68, which has miniDisplay port and now native resolution is supported.

Yes, joy with a simple command that switches back settings to be useful again. It seems Apple are continuing to regress with progress across all their platforms. See below command terminal snippet to get back the full list of accessible resolutions

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

This worked on two OS X Sierra platforms for me, so hope it help you. You will need to re boot after tis op btw

I do not have any Problem.

I have 2 Ultrawide LG monitors connected with my Macbook Pro , using the Type-C to HDMI cable.

Both the Screens are working fine with 2560 x 1080. Even if i open the Lid of my mackbook, it works fine with that also . So all 3 displays are fine.

There is Problem for iMovie users though. iMovie Opens and Closes with a crash message, while you are using External Monitor only.

Here is the workaround for that:

Open the Lid of your Macbook. Start iMovie and then close the Lid. It works fine then.

my problem with my LG UltraWide monitor now, is that it just stretch the 1920x1080 instead as on el capitan where It could go to 2560 x 1080, Seems like Apple just ditches UltraWide support

I told the german technical support hotline about the problem. They said it will most probably be fixed in a future update. To assure this, I would recommend people with the same issues to give Apple a call.

Here another LG ultra wide user 😟

After upgrading to Sierra OS. The native resolution of 2560x1080 is no longer an option!

It believes that 1920x1080 is the native resolution of this monitor. Now I got black bars on both sides.

… and today I got a call back in order to gather some system log files for the technical engineering team. Let´s hope they will fix the issue soon.

Let's hope!

Same issue here with an LG Ultrawide. I called Apple today and they told me it is a known issue that will be fixed in an update soon. They had me put this into the terminal and reboot my computer with no luck, but some have had luck with this if you want to give it a try:

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

I have the same problem on a AOC 3440x1440. The "best" option I get is 1080p. Excruciating.

I'm having the same issue here, I cant believe they shipped the new OS with that bug. What is going on Apple? Did you QA before release?

I was able to fix the problem using the tool SwitchResX by following the steps at

http://terrislinenbach.blogspot.co.uk/2015/12/running-lg-29um57-p-on-old-macbook -pro.html

But SwitchResX is a paid solution, so Apple should fix that soon.

The issue is not Ultrawide-monitor specific. Happens also with my 27" Acer Predator that worked just fine with El Capitan and older macOS. Very annoying as I use the MacBook for work and development. I did not get the 2560x1440p resolution when holding down the option-key. And no mater what other resolution I choose, the screen itself is very small in the middle, with black bars around, does not scale one bit.

So two problems after upgrading to Sierra:

1) Cannot choose proper resolution (2560x1440)

2) Does not scale at all (no mater the resolution)

Created a bug-report with Apple, but still no reply... C'mon Apple, our eyes are bleeding here.