As in earlier Windows Versions the Feature Installation of .NET Framework 3.5.1 in Windows 10 is still needed if you have (legacy) Applications which are depending on it. By default, this feature is not enabled:
If you’re using Microsoft Deployment Toolkit (MDT), enabling NET Framework 3.5 during a Task-Sequence is pretty simple due to a dedicated Step for Roles and Features. If you “just” have Configuration Manager without MDT, you need to do the (little) magic on your own.
1. Mount the Windows 10 ISO and navigate to the following Folder “\sources\sxs”
Starting with Windows 10 the structure of the sxs folder is different from before. With Windows 8 / 8.1 we had around 800 Folders. In Windows 10 this is reduced to one single file called “microsoft-windows-netfx3-ondemand-package.cab”
2. Grab that file and copy it to a new folder on your Package Share. Create a new file called “InstallNetFx3.ps1” in the same folder with the following content:
$currentLocation = Split-Path -Parent $MyInvocation.MyCommand.Path;
Enable-WindowsOptionalFeature -Online -FeatureName NetFx3 -Source $currentLocation -LimitAccess -All