Can't run two fullscreen application on Windows 10

I think you must run one of them as "windowed mode" (or borderless window).

Can't run two fullscreen application on Windows 10

I think you must run one of them as "windowed mode" (or borderless window).

Yes that works, but on Windows 7, I could run two applications on fullscreen without any problems. I did more testing today and some application I can't run fullscreen even in single instance. Borderless window works fine, but older programs does not have this option - I can work around this using some third party application, but even then there are limitations (for example in Killing Floor I can't change brightness/gamma when not in fullscreen).

Why does this doesn't work? Is there a fix? Should I go back to Windows 7? I expected that the functionality will be comparable.

I did more testing and it affects only DirectX 9 applications.

It can be easily tested in Unigine Heaven Benchmark: https://unigine.com/products/benchmarks/heaven/

If I select DirectX 9 and Full Screen I get:

Dirct3D9 error: invalid call
D3D9AppWindow::create_context(): CreateDevice(): failed
Engine:video_restart(): can't set 1920x10980 fullscreen video mode

If I select DirectX 11 and Full Screen then everything is fine.

Could someone please look into it?

It can be easily tested in Unigine Heaven Benchmark: https://unigine.com/products/benchmarks/heaven/

If I select DirectX 9 and Full Screen I get:

Dirct3D9 error: invalid call
D3D9AppWindow::create_context(): CreateDevice(): failed
Engine:video_restart(): can't set 1920x10980 fullscreen video mode

If I select DirectX 11 and Full Screen then everything is fine.

Could someone please look into it?

I've experienced some issues in fullscreen gaming once got to Win10 with this great software and this is how i solved:
for crashing games on startup I ran Game exe on Win7 Compatibility mode,
for fullscreen flickering I had to create a new custom resolution in Nvidia Control Panel, like 1920x1079 and set the desktop res to it,
then i ran the game on native 1920x1080 resolution and it worked fine without any issue,
Haven't tried on other gpu brands tough.

just run all them in borderless window, and make sure you set the res max depending on your monitor. you wont even be able to tell from it being windowed.

for crashing games on startup I ran Game exe on Win7 Compatibility mode

Really works! Thanks fot the tip, no need to disable Aster to play Assassin's Creed II now 🙂