Lost ability to choose 3440x1440 resolution

I'm having the same problem on my macbook air 13in through thunderbolt2. Worked just fine 20 min ago before "upgrading"

I have exactly the same problem with mid 2012 macbook air. Same HD4000 chip. I think

The same problem for me too. 😟

Same Problem here too....Thinking of reverting back to Maverick....this is just "crap", because with Maverick and HD4000 my 3440x1440 was running fine at 50Hz....

Not even virtual Resolution Tools (RDM) or Display Menu are able to read out correctly the monitors correct resolution.....

Same problem here 😟

Try this;

System Preferences > Displays

On the display preference pane for your external display, hold the OPTION button while clicking on the Scaled option.

Does the display resolution you want become available for you to select?

Sorry, just re-read your post, you already tried it.

Same problem with MacMini late 2012 (4 machines)

My MB Air 13, Mid 2013 works.

Got the same problem too.

Not happy about this, considering it was working JUST FINE before the update.

Would not have upgraded had I known.

Can't they fix it? Any work arounds?

I tried to fix it with switchresx and it didn't work. t went back to Maverick😟. Thank god there is time machine. 🙂

Same screen, same problem: MacBook Pro 9,2 (Mid 2012), LG 34um95, Mac OS X Yosemite. Worked perfectly fine under Mac OS X Mavericks.

Anyone any idea on how to fix this issue? HELP would be much appreciated. Shame on Apple to just degrade my 3 week old screen :-(((

another 'me too' post - I have one macbook air thats running Yosemite - the 34um95 runs at 2560x1080@60hz - with an expensive apple thunderbolt cable - on my other macbook air (which I didn't upgrade yet) the screen runs at 3440x1440@50hz 😟

After playing around (unsuccessfully with SwitchResX) I checked my old Backups of the situation a day prior to Upgrade to Yosemite.

Interesting stuff: I restored from an earlier TimeMachine Backup the specific Display Profile File (used on Maverick & Yosemite for 34UM95 --> checked with ioreg command) to my MacBookPro (System/Libraries/Displays/Overrides/DisplayVendorID-1e6d) and so far - even as Dualscreen - my 34UM95 can be used with native resolution 3440x1440 (connected to Thunderbolt). --> so this should work eventually for you guys, having a 34UM95 connected to a MacBook as second screen. In Display Settings (OS X) the resolution 3440x1440 is shown and I can choose between 60Hz (NTSC), 50 or 30Hz PAL

The File used for 34UM95 seems to be "DisplayProductID-76db" (checked on MacBookPro as well MacMini): Prior to Yosemite Update it was from 28th Feb. After Yosemite it has ChangeDate of 9th September. Internally (binary/hex coded settings) it seems to be different to the Yosemite version as well in Yosemite there is a string attribute LG ULTRAWIDE, where as the old file just keeps the same values 7789 for VendorID and DisplayProduct 30427

On my MacMini I unfortunately started TimeMachine Restore back to Maverick yesterday (still restoring). Eventually I will upgrade again to Yosemite and try to exchange this File with Maverick version.....on my MacBookPro (Late2013, 13'') it seems to work some, though....

This sounds like a real deal - unfortunately the file you mentioned - on my time machine backup - is from July. I tried to simply replace the Yosemite-File and it didn't work. I rebooted the machine and held down the option key while clicking on "scaled" - nothing :-/ Is there a way you could post or send this file to this group? Help is very much appreciated :-)

Thank you for your helpful post!

Regards, Frederic

thanx fboesch for little workaround, but it not help.

I tried clean install also and not work, the install software also just work in a 2560x1080 resolution.

I replace older display overrides, but no changes.

Just my MB Air MacBook Air (13-inch, Mid 2013) works great after update with 3440x1440 and 34UM95 (Display Overrides also 9.9.14).

Could you possibly also mention what MacBook Pro you are using? THANX