Just like with Windows 10, Windows 11 also comes with only .NET Framework version 4.x pre-installed. If you try to run any application written using any older versions of the .NET Framework such as 3.5, 3.0 and 2.0, then you will have to first install those versions of Framework on your Windows 11 PC.
There are two ways of installing .NET Framework 3.5 on your Windows 11 PC. The first method involves downloading and installing the .NET files from the internet. The second method does not require internet access and only requires the Windows 11 DVD or Windows 11 ISO image file.
Enabling .NET Framework 3.5 Online:
- Press the hotkey Win+R to open the Run dialog. In the Run dialog, type appwiz.cpl and press Enter.
- In the Programs & Features window, click on the Turn Windows Features On or Off.
- Select .NET Framework 3.5 (includes .NET 3.0 and 2.0) and then click on the OK button.
- Wait for it to download the required files from the internet and install it on your system.
Enabling .NET Framework 3.5 Offline:
- Insert the Windows 11 DVD in your computer’s DVD drive. If you have a USB pendrive containing Windows 11 installation files, then attach it to your PC. If you have Windows 11 ISO, then mount it as a virtual drive. Only any one of these is needed. We are assuming that any one of these is available through the D: drive.
- Press Win+X and then select Windows Terminal (Admin) from the menu.
- In the Terminal window, give the following command:
DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /LimitAccess /Source:d:\sources\sxs
- Wait for it to install the .NET Framework 3.5 on your PC. When it shows 100%, you have .NET Framework 3.5, 3.0 and 2.0 installed on your PC. Usually the process takes less than 5 minutes.
So these are two ways of enabling .NET Framework 3.5 on your Windows 11 PC. You can choose any one of them depending on which one you find easier.