How to install dotnet 3.5 offline in Windows 10

As a Windows user, you've probably at least once come across the words ".NET Framework." It's a Microsoft-developed software framework that lets you build and run C#, C++, F#, and Visual Basic programs. The latest .NET version is 4.8, but your computer may need an older version of .NET (like .NET 3.5) to run some apps.

Fortunately, installing .NET version 3.5 is fairly easy. So, let's explore how to double-check if your PC already has .NET 3.5 installed, and what to do if it isn't.

Is .NET Framework 3.5 Installed on Your PC?

Before we head into installing .NET 3.5, it's a good idea to check if you've already installed it in the past:

1. Press Win + R, type control, and press Enter to launch Control Panel.
2. Click on Programs > Programs and Features.
3. From the left pane, select Turn Windows features on or off.
4. You'll see .NET 3.5 at the top of the list of Windows features. If the box besides .NET 3.5 is shaded in black, it's installed.

Notice how there's a bracket that says that this version includes .NET 2.0 and 3.0. This means THAT when you install .NET Framework 3.5, you'll also be able to run any apps that require .NET 2.0 and 3.0.

If the box beside .NET Framework 3.5 is not shaded in black, that means it is not installed on your computer. As such, you can then use one of the following three methods to get it installed onto your system.

Install .NET 3.5 From Windows Features

If you followed the above steps to figure out if your PC has .NET 3.5 Just follow the steps in the previous section to get to Windows Features.

All you need to do then is select the box besides .NET Framework 3.5 and press OK to exit the window. Windows will begin installing .NET Framework 3.5 immediately, but you'll need to restart your PC to complete the installation.

If you don't have an internet connection on your PC, you could use a Windows DVD or bootable flash drive to install .NET 3.5. It's fairly simple and doesn't take a lot of time, provided you have the Windows installation media.

1. Insert the installation media into your PC and look at the drive letter assigned to it,
2. Press Win + R, type cmd, and press Ctrl + Shift + Enter to launch Command Prompt as an administrator.
3. Execute the following command:

    Dism /online /enable-feature /featurename:NetFX3 /All /Source:G:sourcessxs /LimitAccess 

   It's assumed that your installation media is assigned the drive letter G. Replace the G with the letter assigned to the drive on your system.

4. The installation will take a few minutes. Once it's complete, restart your PC.

Install .NET Framework Using Offline Installer

If you fancy doing a direct download, Microsoft has an offline installer for previous versions of the .NET framework on its dotnet website. However, before you venture forth and download one of the files, make sure that you're downloading a supported version of .NET.

Fortunately, Microsoft makes it very easy to download a supported version. When you access the download page, the website will automatically expand the list of supported versions and hide the unsupported ones. And you'll find .NET 3.5 listed as a supported version, as shown below.

It's important to download a supported version, as Microsoft set "end of support" dates for its software, after which the software giant will stop releasing updates for it. Fortunately, at the time of writing, .NET 3.5's expiry date is set for October 10, 2028, so you have plenty of time to use it.

Once you've downloaded the offline installer for your chosen version, you're ready to begin the installation. In most cases, your installation should be smooth sailing. Sometimes, though, the offline installer just doesn't want to play ball.

Install .NET Framework Using Command Prompt or PowerShell

If you like to get things done quickly, you could use either the Command Prompt or the PowerShell to download and install .NET Framework 3.5 with a single command. Here's how to do that:

1. Press Win + R, type cmd, and press Ctrl + Shift + Enter to launch an elevated Command Prompt. If you want to use PowerShell, type powershell instead of cmd.
2. Run either of the following commands depending on whether you're using the Command Prompt or the PowerShell: Command Prompt:

    Dism /online /Enable-Feature /FeatureName:"NetFx3" 

   PowerShell:

    Enable-WindowsOptionalFeature -Online -FeatureName "NetFx3" 

3. This will trigger the installation. Once the installation process ends, you can exit the Command Prompt or PowerShell.

Confirm the Successful Installation of .NET Framework 3.5

Once you've installed the .NET Framework, you could verify successful installation by running a command in an elevated Command Prompt.

1. Press Win + R, type cmd, and press Ctrl + Shift + Enter to launch an elevated Command Prompt.
2. Execute the following command:

    reg query "HKLM\SOFTWARE\Microsoft\Net Framework Setup\NDP" /s 

3. You'll see all the installed versions of .NET Framework on your system.

.NET Framework 3.5 Installation Problems

There are a number of reasons why you could run into a problem while installing .NET Framework 3.5. For instance, if your copy of Windows is not licensed, .NET Framework won't install on your system. The only way out is to activate your current copy or get a new Windows 10 license.

The installation process may also sometimes require you to download a handful of Windows updates, though this is more a problem with newer versions of the .NET Framework unless you haven't updated your computer since the stone age. It will give you a KB number that you can use as a reference and get those updates installed.

If you've purchased your PC anytime during the past 10 years, it's unlikely your PC won't support .NET Framework version 3.5. Regardless, you can always go ahead and check what versions of .NET Framework will work on your OS.

.NET Framework works on all Windows operating systems from Windows Vista onwards (i.e. Windows 7, 8, 8.1, and 10), though it doesn't come pre-installed with Windows Vista.

You're Set to Run .NET 3.5 Programs

Hopefully, you were able to successfully install .NET 3.5 without running into issues. You should now be able to run all programs that require 3.5. You should also make sure that you have the most current .NET Framework installed as well, of course.