Windows – Win10 Unable to install .NET Framework 3.5

.net framework.net-3.5windows 10

Just switched to Win 10 from Win 8.1. A program is giving an error at startup (C:\Windows\Microsoft.NET\Framework\v2.0.50727\mscorlib.tlb could not be loaded)
so I tried to reinstall .NET Framework.

I've tried with all the possibilities I've found and even installing some components that indirectly install it but alway it ends with:

.NET Framework 3.5 (includes .NET 2.0 and 3.0)

The system cannot find the file specified. Error code 0x80070002

I've spent a lot of time searching possibilities, let's see if anyone has a clue or an undesired revert to Win8.1 is on the horizon…

UPDATE:
From the suggestion in a comment by @magicandre1981: Can't install .net 3.5 on Windows 10

Pointing to: https://blogs.technet.microsoft.com/mniehaus/2015/08/31/adding-features-including-net-3-5-to-windows-10/

I executed:

DISM.EXE /Online /Add-Capability /CapabilityName:NetFx3~~~~ 

And it worked! 100% completed without problems. Now almost all is fixed except when I try to open a Properties window on Visual Studio 2008 (the main user of the .NET 3 it says

Failed to create .NET Frameworks PropertyGrid component. Please
verify that the Common Language Runtime and .NET Frameworks are
properly installed.

Haven't dug deeper but I hope to fix this -hopefully- last one.

Best Answer

If you have windows 10 installation media (DVD, ISO, USB) attach it. Run cmd as admin and run:

dism /online /Enable-Feature /FeatureName:Netfx3 /All /LimitAccess /Source:E:\sources\sxs

Where E:\ is the drive letter assigned to installation media. If you still get error, you have to uninstall every update to NetFx4.5, then repeat steps above, and again update NetFx4.5 as stated here. Also check out here if you're joined to domain.