UE 5.6 C++ Compile Failure — UnrealBuildTool Broken After Full Reinstall

Development Programming & Scripting
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Hi all,

I’m deep in development on a MetaHuman-based AI system that integrates Azure Speech SDK, real-time viseme sync, and a custom TCP server for NPC interaction—and I’ve hit a wall that even clean reinstalls haven’t fixed.

After upgrading and reinstalling UE 5.6 and Visual Studio (with all relevant workloads), I’m seeing the following issues on every C++ project (new or existing):

  • .sln files fail to generate or open with empty/incomplete modules
  • UnrealBuildTool.dll silently fails or is missing
  • IntelliSense browsing DB (Browse.VC.db) is locked across sessions
  • Visual Studio toolchain won’t register Unreal targets correctly
  • No plugins enabled—this happens even on base template projects

Steps I’ve already tried:

  • Full reinstall of Epic Games Launcher and UE 5.6
  • Fresh VS2022 install (w/ Game Dev + Desktop Dev workloads)
  • Manual deletion of .vs, Intermediate, Binaries, and cache folders
  • Creating new Windows user profile
  • Killing ghosted devenv.exe processes
  • Setting fallback IntelliSense path in VS config
  • Submitted a support ticket (awaiting confirmation)

This issue is blocking delivery on a project with potential large-scale impact in AI-human interface tech. If anyone has seen similar behavior—or knows whether this is a known UBT regression—I’d love insight.

Thanks in advance.

— Jared
Windows 11 | Visual Studio 2022 | UE 5.6 (binary install)

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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 likeC:/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.
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Thanks for your response! It wasn’t the solution I needed this time, but it did help clarify a few things I hadn’t considered, especially around build setup and potential tooling conflicts. I’ve since moved on to building UE from source just to eliminate some of the variables, and I’ll revisit your suggestion if anything loops back. Appreciate the support!

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