How to Install .NET Framework 3.5 in Windows 11

If you’re trying to run older applications on Windows 11, you might encounter an error asking you to install .NET Framework 3.5. This version is essential for compatibility with legacy software that was built on older versions of Windows. Although Windows 11 comes with .NET Framework 4.8 preinstalled, some programs still depend on .NET 3.5 to function properly.

In this guide, we’ll walk you through how to install .NET Framework 3.5 in Windows 11 using several methods — from Settings to Command Prompt and even offline installation.

Method 1: Install .NET Framework 3.5 from Windows Features

1. Press Windows + R, type optionalfeatures, and hit Enter.
2. In the Windows Features window, check the box next to .NET Framework 3.5 (includes .NET 2.0 and 3.0).
3. Click OK to begin installation.
4. Windows will automatically download the required files and install .NET 3.5.
5. Once complete, restart your PC to finalize the setup.

This is the easiest and most direct way to enable .NET 3.5 if your PC has an active internet connection.

Method 2: Install .NET Framework 3.5 via Command Prompt

If the graphical interface doesn’t work, you can use Command Prompt with administrative rights.

1. Open Command Prompt as Administrator.
2. Type the following command and press Enter: DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /LimitAccess /Source:D:\sources\sxs (Replace D: with the drive letter of your Windows installation media.)
3. Wait for the process to complete.
4. Once it’s done, restart your computer.

This method is especially helpful if you’re working on an offline machine or facing Windows Update issues.

Method 3: Install via PowerShell

PowerShell offers another quick way to enable .NET 3.5.

1. Open PowerShell as Administrator.
2. Run the following command: Enable-WindowsOptionalFeature -Online -FeatureName NetFx3 -All
3. Let the installation finish and then reboot your PC.

Method 4: Offline Installation Using Windows ISO

If you don’t have an internet connection, you can use a Windows ISO file or installation media.

1. Insert your Windows 11 ISO or USB drive.
2. Note the drive letter (e.g., D:).
3. Run Command Prompt as Administrator.
4. Enter this command: DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /Source:D:\sources\sxs /LimitAccess
5. Wait for the installation to finish, then restart your PC.

Why .NET Framework 3.5 Is Important

Many older applications, especially enterprise software and legacy games, still rely on .NET 3.5 components. Without it, you might encounter errors like “The application failed to initialize properly” or “Missing .NET Framework version”. Installing this framework ensures full backward compatibility with older software on Windows 11.

Final Thoughts

Installing .NET Framework 3.5 on Windows 11 is a straightforward process, but the method you choose depends on your setup. For most users, enabling it through Windows Features works fine. However, if you face network or update issues, using the Command Prompt or offline installation method is the best alternative.

Once installed, you’ll be able to run older applications smoothly — making your Windows 11 system both modern and backward compatible.