[Fix] .NET Framework 3.5 Error 0x800f0950 in Windows 10/11

.NET Framework is a software framework used by many Windows applications. Some programs developed on a specific version of Visual Studio require a particular version of the .NET Framework. Many companies develop their apps to run using the .NET Framework, and these apps target a specific version. If you see this pop-up, you’re trying to run an application that requires the .NET Framework version 3.5, but that version is not installed on your system.

Clicking Install this feature will install .NET Framework 3.5 via Windows Update. Alternately, you can enable the .NET Framework 3.5 through the Windows Control Panel. This option requires an Internet connection.

Install .NET Framework 3.5 Using Windows Features

1. Right-click Start, click Run. Type OptionalFeatures.exe, and press Enter.
2. In the “Turn Windows features on or off” dialog box that appears, select the .NET Framework 3.5 (includes .NET 2.0 and 3.0) check box.
   
3. Select OK, and reboot your computer if prompted.

You don’t need to select the sub-items “Windows Communication Foundation (WCF) HTTP Activation” and “Windows Communication Foundation (WCF) Non-HTTP Activation” unless you’re a developer or server administrator who requires this functionality.

Install .NET Framework 3.5 Using Windows Setup Disk & DISM

In some systems, .NET Framework 3.5 installation error 0x800f0950, 0x800F0906, 0x800F081F or 0x800F0907 may occur. For example, here is an error message:

The following feature couldn't be installed:

.NET Framework 3.5 (includes .NET 2.0 and 3.0)
Error code: 0x800F081F

In those cases, you can try installing the feature from the Windows 10 DVD or ISO. However, you must make sure that the Windows 10 version on your DVD or ISO corresponds to the version of Windows 10 installed on your system.

Option 1: DISM: Windows 10 Setup media as the source

1. Obtain the latest Windows 10 ISO (assuming that your Windows 10 system is running the newest build) using the Media Creation Tool, and then mount the ISO image.
   

   

2. Note down the drive letter of your DVD or the mounted drive, let’s say H:\
   
3. Open an elevated Command Prompt (Administrator) window.
4. Type the following command, and press ENTER

   dism /online /enable-feature /featurename:NetFX3 /Source:h:\sources\sxs /LimitAccess

   

Note: If you need to install the “Windows Communication Foundation (WCF) HTTP Activation” and “Windows Communication Foundation (WCF) Non-HTTP Activation”, make sure you add the /All parameter, as seen in the above screenshot. As said earlier, these two components are usually not required for most users.

Option 2: DISM: Windows Update as the source

Alternately, to use Windows Update server as the source, run this command:

dism /online /enable-feature /featurename:NetFX3

The above command installs Install .NET Framework 3.5 feature files from Windows Update. Then try enabling .NET Framework 3.5 again via Windows Features and restart Windows.