I understand that you would like to install the .Net Framework 3.5 feature on Windows 10 Technical Preview.
The .NET Framework is an integral part of many applications running on Windows and provides common functionality for those applications to run. Normally, before running/installing such applications, we need to enable .NET Framework from the Control Panel on the computer. So, you may first check if the .NET Framework 3.5 is available in the Control Panel on Windows 10 Technical Preview and if available, you may enable it from the Control Panel to install it on the computer. To check if the.NET Framework 3.5 is available in Control Panel and to enable it, please follow these steps:
a) Press “Windows Logo” + “R” keys on the keyboard.
b) Type “appwiz.cpl” in the “Run” command box and press “ENTER”.
c) In the “Programs and Features” window, click on the link “Turn Windows features on or off”.
d) Check if the “.NET Framework 3.5 (includes .NET 2.0 and 3.0)” option is available in it.
e) If yes, then enable it and then click on “OK”.
f) Follow the on-screen instructions to complete the installation and restart the computer, if prompted.
This will install the .NET Framework 3.5 feature on the computer. There is also another way by which .NET Framework 3.5 gets installed on the computer. This is done by the apps on demand.
If an app requires the .NET Framework 3.5, but doesn’t find that version enabled on your computer, it displays the prompt for installing the .NET Framework 3.5 on demand, either during installation, or when you run the app for the first time after its installation. In this prompt, you can choose the option “Install this feature” to enable the .NET Framework 3.5 on the computer.