Why are shaders compiling every time I open a map.

Every time I open a map all my shaders are recompiled. That’s sounds strange, cause I’ve my shaders already compiled… Any idea? It’s taking like forever every time I change to a different map…

I have this issue as well… Kinda a killer when we are working on stupid large maps with 72,000 shaders being compiled every time.


Our team has the same problem. Every time we open our map, all shaders are compiling (over 7000) and it takes 5-10minutes before we can work.

Doesn’t compiled shaders save somewhere?

Hi everyone,

If you could please provide the info below.

  • What version of the editor are you currently using?

  • Does this also occur when testing in a new project?

  • Post your dxdiag.

We figured out the issue.

So we had a ton of road splines in the map using the same material as everything else.
However, we didn’t check “Used With Spline Meshes” in the material. So unreal was auto-checking that on in the background every time we opened the map causing all of the shaders to recompile over the already compiled shader cache from before. Once we checked on "“Used With Spline Meshes” in the material, the problem was fixed.

So… it would be nice if there was a visual warning that popped up saying that it auto checked it for us, or if it made changes to the material directly and just needed us to save the material. But idk. Regardless, it was a huge headache for something so simple.


1.We are currently using 4.4.2 on few post and 4.4.3 on other.
2. No, only in our project. It started yesterday.
Thank you!

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You are right! We used our mastershader for all assets in a scene. One of them is apex cloth and our main character. We created a new material only for them and the shadier compiling stopped!

For anyone encountered this problem after 4.15, possibly, you need to re-save materials. Unreal saves some steaming data into materials, you may need to re-save relative materials after you have modified map lighting or something else. Check “Output Log” to know which materials you need to save after loading map. For more information, check unreal doc Texture Streaming, good luck.