Q: 34" LG Ultrawide and MBPR 15"Sierra resolution issue

Actually, I have 25" model UM25. However, Sierra recognizes it as UM34 anyway and I'm having exactly the same issue. I updated to Sierra yesterday.

I am having the same issue!

Same here, I am have a 29 LG, upgraded to Sierra and this resolution problem started. 

Same issue. 3440x1440 Acer Predator. Can only put it up to 1080p.

Same issue here. 29'' LG display.

Hello #y.choi,

Can you please share how you solved this issue?

Thank you.

Exactly same issue here. I'm using a 29UM65 Display and all I got is 1080p resolution. And it seems that no official reply was made.

Sorry to confuse you.I did not solve the problem yet. I just wanted to say I have the same problem.

Besides, I'm having a temporary solution, by setting the monitor aspect ratio as 'original' from the monitor side.

     monitor menu/quick settings/ratio/original.

This setting gives me a temporary relief. Hope this help you. Thanks.

Same problem here. On some forum I saw someone having success with http://www.madrau.com/. I'm not particularly keen to pay for this though.

I think this issue is related with HDMI support.

I tried both LG 29UM57 (HDMI) and LG 34UC97 (Thunderbolt), it doesn't support 29UM57 but support 34UC97, which even has higher resolution.

(BTW, using Mini-Display / Thunderbolt to HDMI adapter doesn't help.)

Same issue with MBP - 25 inch LG ultra wide -Worked just fine before Sierra, after reboot. won't support full resolution.

FIX THIS ***

I tried it (switchresX) custom display is not working on sierra.

Here is what I tried and doesn't work

- option click "Scaled"

- SwichResX

- QuickRes

- buy a thunderbolt to HDMI cable

- pray for apple release a new update

this says solved but it has no solution.

I am having the same problem.