Bull Cow game flickers

When I load bullcowgame.uproject, I get black and yellow flickering in the central “window” of the editor. I let shaders compile, I clicked "Build " and “Compile” and it still happens. I’m using Linux and release (4.26) version of the editor. Any advice?

Just the window? As in this thing?

Yes, only that one. And instead of the above picture I only see black and yellow flickering. Loading still happens correctly.


But when it completes instead of the above screen, all I see is alternating black and yellow. Note that the numbers, the Z X Y axes are still visible normally.

Other than being annoying, is there anything stopping you from progressing?

Well, yes, because I can’t get past lesson 37 in the Unreal Course. For example in the tutorial there is some clicking around in the viewport and observation of things in the details tab. And I dont see what i’m clicking on. Fence? Group of trees? Landscape? etc. In lesson 38, when I open the second viewport, I can’t move around due to all i see is quickly alternating black, yellow and some colors filling the entire viewport (instead of the road, landscape etc) like in above screenshot.

Oh I thought you just meant just during compiling it flickers and then it’s fine after that. So you have to restart the editor?

I open through clicking .uproject. Flickers right from the beginning. Closed it, opened it again, still flickers all the time. I dont even have any idea what causes it.
No matter how many times i restart, in the viewport there is only black-yellow-other colors constantly alternating.

What branch/tag are you using for UE4? I would suggest using the release branch if you’re not already using that. Changing version would mean you would need to recompile both Unreal and the BullCowGame project.

I downloaded the latest branch. So its 4.26+
This one:


I think you might need to contact Epic support on this one as the only suggestions I have is making sure everything is up to date on your system and recompiling Unreal.

Compiling took me almost whole day. So I’d rather put that as last resort. I try contacting Epic Support.