Hey there @FallguysJodie! Welcome to the community! Taking a glance into the engine source code, that line specifically points to a shader pre-caching issue, which could be environmental like drivers (so you already tried to backdate them so that’s unlikely).
So my first thought is to verify if this occurs in every 5.4.4 project and not just the one you’re working in. If possible can you check if it works in another project at all? If it does, is it specific to some materials or all of them in your primary project?
It’s all materials and also static mesh editor too. I just found out. If I open an existing one it works but not if I convert a 5.3 one to 5.4. I also noticed it loads the project very quickly there is never the pause to compile shaders when I start from a template yet there is when I open a converted one.
Gotcha! So first back your project up somewhere safe. Then go into the project’s files and delete/move the “DerivedDataCache”, “Saved”, and “Intermediate” folders entirely. Then launch the project. This will rebuild the shaders. If that doesn’t have an effect, head into your Unreal Engine install and delete the “DerivedDataCache” folder there as well. This will regenerate all shaders associated with both the engine and the project itself.
I was late to the conversation. But, I was going to mention removing/regenerating your DefaultEngine.ini and see if it fixed it, assuming that it was only happening in one project. I’m glad that you got it fixed, though!