Can't install .net 3.5 on Windows 10

Please open a command prompt (cmd.exe) as admin and run the following command to install .Net 3.5:

DISM /Online /Enable-Feature /FeatureName:NetFx3 /Source:d:\sources\sxs /All /LimitAccess 

(replace D: with your mounted Win10 ISO)

In some environment, DISM fails to fetch the file (Proxy, network policies). The DISM command takes the files from the DVD and you're fine.

If you are MSDN subscriber you can also download the Windows 10 Features on Demand ISO, mount the ISO, copy the to C:\Features (or a different folder) and those commands:

DISM.EXE /Online /Add-Capability /CapabilityName:NetFx3~~~~ /Source:C:\Features

If this fails, run this:

DISM.EXE /Online /Add-Package /PackagePath:C:\Features\