Hey there @Darken1! Welcome to the community! So this issue is primarily due to a shader cooking improperly or an issue with already cached data. Like Ghost mentioned, I’d first take a look at your build log to see if the error was mentioned there in more detail. Otherwise some general fixes before getting to more specifics would be to back your project up somewhere safe, and delete the Intermediate and Derived Data Cache folders under the Saved Directory then attempt a clean build. Since it’s mentioning a global shader, I would also verify the engine’s installation from the launcher just to be safe.