I’m seeing the same failure:
Unhandled exception: System.IO.FileNotFoundException: Could not load file or assembly ‘C:\Program Files\Epic Games\UE_5.1\Engine\Binaries\DotNET\UnrealBuildTool\Plugins\ScriptGeneratorUbtPlugin\ScriptGeneratorUbtPlugin.dll’. The system cannot find the path specified.
I installed 5.1 from the Launcher with all options enabled, but no other platforms (Android, etc.) installed. Windows Desktop is implicit.
To update my existing 5.0.3 game project, I switched versions from 5.0 to 5.1 via File Explorer RCLICK on the .uproject, and that triggers a re-generation of the VS project files. In other words, this issue is a BLOCKER for people who have a C++ game project but use a binary UE installation (do not build the Engine).
So what needs to be done to fix or work around this? Is there some way we can escalate this so Epic devs are even aware of it?