Не устанавливается .NET Framework 4 - Microsoft Q&A

To ensure security, it is best to obtain Windows updates directly from official sources:

Download and run the CheckSUR tool (also known as the Deployment Image Servicing and Management - DISM tool on newer versions) to repair corrupted system files.

file if you are performing a manual installation of .NET components or if an automated installer (like those for Autodesk or gaming platforms) fails to fetch it. Microsoft Learn Where to Download