UE5 (5.1) error when start

Looks like the shader handler is failing. This could be due to a hardware incompatibility, DX12/SM6 failing, and many other possible issues. Since it’s shader based, we’ll treat it like a GPU issue first and see if that allows you to launch. Follow some of the fixes in this thread first, specifically disabling any GPU tapping services and trying to downgrade to DX11 to see if the engine itself actually makes it to launch. If it does, then turning off TAA/TSAA in project settings since that can cause some shader mishaps on some systems.

Let me know if none of these help.