After decades of supporting enterprise IT, this is the honest truth:

After enabling .NET 4.8 via Windows Features, open an elevated Command Prompt and type: reg query "HKLM\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\full" /v version

Interestingly, .NET Framework 4.0 is handled by a different mechanism. Here is the correct procedure:

To install .NET Framework 4.0 version 4.0.30319 on Windows 10 64-bit, follow these steps:

First, let’s break down the technical jargon.

You may need .NET Framework 4.0 if: