If you've hit Error 25007: Error occurred initializing fusion. Setup could not load fusion with LoadLibraryShim() — it usually means a previous .NET installation is corrupted or partially removed.
Resolution steps:
- Download and run the .NET Framework Cleanup Tool to remove all traces of previous .NET versions
- Reboot the machine
- Reinstall the target .NET Framework version from the standalone installer
- Run Windows Update to apply all .NET patches
Modern context: .NET Framework (up to 4.8.1) ships as a Windows component and is serviced via Windows Update. The newer .NET (5/6/7/8+) is cross-platform and doesn't rely on the Windows fusion loader at all. If you're building new applications, target the modern .NET runtime — it's faster, more secure, and avoids the legacy Framework dependency chain entirely.
For legacy applications that require .NET Framework: ensure it's deployed as part of your base image and managed through WSUS or MECM compliance baselines.