Using a .cab file from a different Windows version (e.g., using a Windows 10 1909 file on a 2004 system) often fails. Always match the file to your OS build. How to Install Using DISM
While Windows 10 and 11 come with .NET Framework 4.x pre-installed, they do include .NET 3.5 by default. Microsoft treats it as an "optional feature on demand" (FOD). You need it because: Microsoft-windows-netfx3-ondemand-package.cab Download
Practical example: Enabling .NET 3.5 from installation media Using a
