Hi, I just bought a new Widescreen monitor with a resolution of 3440x1440 (21:9), the only problem is that the game does not have the option to set this resolution, 1920x1080 (16:9) is max.

I tried installing a software called Flawless widescreen monitor, but it stops working for some reason, and also witcher 3 is not added to this program..

I also tried adjusting the User.settings file and changed the Horizontal frame scale and such, but it just ignores these values.

Anyone has a fix for this problem, the game is now stretched over the entire screen, or if you use borderless windows you just see a borderless window of 1920x1080 in the middle of the screen...

Thanks in advance

That's because it's not fully supported. You may find some help here if you're prepared to use other peoples' executable files.

Hm,

Didn't need a fix (software or ini-Files) at all to run it with full resolution, BUT:
I had to change Display Mode to "Fullscreen" instedd of preselected "Borderless Windows" - because that only offers 16:9 resolutions.

My setup (AMD Fury X - LG 34UC88-B) with all setting @Ultra (but without any hairworks).