Hey there @JxCoZ! Welcome back to the community! The AmbientCubemapCompositePS is usually part of your lighting setup to composite the ambient lighting for the scene. If this is exceptionally heavy or something is wrong with the shader (like corruption) you may be able to rebuild shaders to correct this.
Does it crash every time or only rarely? Is the lighting complexity or the level size out of the ordinary?
Rebuilding Shaders (and other caches)
First back up your project somewhere safe in case this breaks anything else, I would recommend source control, and save your editor layout if you’d like. This step is crucial when messing with project files directly.
Make sure the project is closed
Then find these files in your project folder:
Intermediate
DerivedDataCache
Saved
Delete them, and then launch the project. It will then rebuild all the shaders and caches that we deleted. Wait for them to fully complete once you’ve opened to your starting level. Once all shader work is done, try to open the heavy level.
Hi, thank you for your answer. I have tried rebuilding shaders deleting the folders you told me, but it still happened sometimes.
It happened frequently, but it did not happen everytime, and I figured that it did not happen when I open the level in Unlit, so I think it is because the lighting as you said, but the cubemaps I am using are not exceptionally heavy, in fact I only use 2 and one of them is the default GreyTextureCubemap from Unreal.
I tried changing the other cubemap I had to the GreyTextureCubemap as well to see if that cubemap being heavy was the problem, and I think it was? Since I changed that, I have opened the level 5 or 6 times, and I did not get any crash!