Sometimes the launcher itself gets confused.
When you run the UE4PrereqSetup_x64.exe , it typically installs or updates the following: ue4 prerequisites x64 setup exclusive
Before we fix it, let’s understand it. Unreal Engine doesn’t run in a vacuum. It needs specific C++ Redistributables, DirectX runtimes, and .NET frameworks to talk to your graphics card and Windows OS. Sometimes the launcher itself gets confused
If the UE4 Prerequisites setup fails with errors like 0x80070643 or 0x80070001 , use these proven fixes: sfc /scannow that configures the essential shared components
This usually means the prerequisites are already installed. You can select "Close" or manually run the installer from the game's Redist folder.
sfc /scannow
that configures the essential shared components required to run Unreal Engine 4–based games and applications on Windows Core Feature: Dependency Management Its primary "feature" is the automatic consolidation of system dependencies