Upd - Microsoft-windows-netfx3-ondemand-package.cab -extra

Then manually copy the extracted CAB contents to: C:\Windows\WinSxS\

Because modern operating systems like Windows 10, Windows 11, and Windows Server do not pre-install .NET 3.5 by default, this file acts as a package. It allows environments restricted from accessing the Internet to complete installations seamlessly via the Deployment Image Servicing and Management ( DISM ) utility. What is the NetFx3 On-Demand Package? Microsoft-windows-netfx3-ondemand-package.cab -Extra

Even with the right file, users may encounter errors. Here is how to resolve the most common ones: Then manually copy the extracted CAB contents to:

If you are truly desperate (and on a non-domain, isolated machine), you can force-enable .NET 3.5 via registry changes. , but it works for the "Extra" stubborn cases. Microsoft-windows-netfx3-ondemand-package.cab -Extra

Add-WindowsCapability -Online -Name NetFx3~~~~ -Source "D:\sources\sxs"