macOS Sierra no longer supports ultrawide monitors?

This fixed mine today!

I bought that app two days ago thinking about hacking this problem but I was not able to find the right combination.

Thank you so much!!

Now to wait for Apple for the right update.

Hello everyone,

I just saw this problem mentioned with at least one suggestion for a fix:

http://mjtsai.com/blog/2016/09/27/sierra-drops-hidpi-scaling-on-external-display s/

I found a way to fix this for my monitor!!

So everyone's using SwitchResX ($16), but I found that since my monitor supports a DisplayPort connection, I switched from HDMI to DP using this cable ($9).

The problem is gone, and I'm back to being able to use my monitor.

I know this can't help anyone without an HDMI alternative, but it seems like Apple just dropped support for native resolution on high-res monitors over HDMI.

For those who want a quick primer on display ports: https://www.youtube.com/watch?v=f38sotYHqtA

(updated video link to a newer video)

P.S. I just found that some minor input lag when watching high-res video full screen is no longer present after switching away from HDMI.

Thank you for letting us know!

Hi, same problem with my late 2012 MacBook pro and my new (and working great in el cap) LG UltraWide 29UM58.

I want anyone else who has this combo to know that the SwitchResX fix did not work in my case, so just keep in mind that YMMV.

Why do you assume that among Apple's employees and testers that someone happens to have one of the monitors experiencing this issue?

It's inevitable that as soon as a product is released, issues like this turn up as Apple can't have one of every conceivable configuration, nor can testers necessarily have one.

I had the same problem with the 29" LG Ultrawide w/ HDMI only, while I didn't have any problem with the 34" LG Ultrawide w/ Thunderbolt.

I just upgraded to the latest Sierra 10.12.1 and it's fixed!

It's incredibly clear and way better than it was using SwitchResX which letterboxes left and right using 2560x1440 and loses the high resolution too.

Thank you apple!

I FINALLY found the fix! I've read so many threads on the Ultrawide monitors in the recent month. I'm using an LG 34" (IPS LED) Ultrawide "diagonal" monitor and was unable to view the image properly, it stretches horizontally and I'm using it behind an easel while painting with oils on canvas, referencing videos and photos is very important during the final glazes. Anyway, I tried various cables, various adapters, option key (of course), the SUDO command (reversed command after it did not work), all with the same image/display results; yes I could see the image but it was a maximum display of 1920 (or 1080p) and not showing the 2560x1080. The app idea is ok however, after reading the details, the app only scales/stretches instead of allowing or enhancing the actual quality of the image. I read above that the Apple customer service's last given advise was to use a "hub" and I had totally forgot that I use the Elgato hub, purchased one with each Mac, recently. The Thunderbolt 2 Dock does have drawbacks, in my opinion and during my experience, i.e., undocking or ejecting peripherals overnight, for instance, which is why I didn't connect it sooner.

Long story short, I'm attaching an image of what you want to see when using the UltraWide monitors, the display default is correct for the LG display (I bet the curve will work brilliantly for my requirements).

THANK YOU FOR ADDING THE INFORMATION TO FIX THIS!

Finally!

in Display pane double tap the scaled while using the option key.

Did you find a work around?