Hard to know exactly without actual error messages and/or dumps, but here are some blind guesses to try:
- A fairly “common” issue with UE on Windows is long paths exceeding the Windows limit. If your project and/or UE installation is in a deeply nested hierarchy (as in, not something short like
C:/Documents/MyProject) I’d research this known issue and look into either migrating the project or enabling “long path support” in Windows. - If your UBT is acting out without helpful error output, you can open UBT’s solution in
Engine\Source\Programs\UnrealBuildTool(within your UE installation folder) and debug it to see what’s wrong.