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Install the .NET Framework 3.5 on Windows 11, Windows 10, Windows 8.1, and Windows 8

• Article
• 07/23/2022

In this article

You may need the .NET Framework 3.5 to run an app on Windows 11, Windows 10, Windows 8.1, and Windows 8. You can also use these instructions for earlier Windows versions.

Download the offline installer

The .NET Framework 3.5 SP1 offline installer is available on the .NET Framework 3.5 SP1 Download page and is available for Windows versions prior to Windows 10.

Install the .NET Framework 3.5 on Demand

You may see the following configuration dialog if you try to run an app that requires .NET Framework 3.5. Choose Install this feature to enable .NET Framework 3.5. This option requires an Internet connection.

Why am I getting this pop-up?

The .NET Framework is created by Microsoft and provides an environment for running applications. There are different versions available. 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 .NET Framework version 3.5, but that version is not installed on your system.

Enable the .NET Framework 3.5 in Control Panel

You can enable the .NET Framework 3.5 through the Windows Control Panel. This option requires an Internet connection.

1. Press the Windows key
   
   on your keyboard, type "Windows Features", and press Enter. The Turn Windows features on or off dialog box appears.
2. Select the .NET Framework 3.5 (includes .NET 2.0 and 3.0) check box, select OK, and reboot your computer if prompted.
   
   You don't need to select the child items for 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.

Troubleshoot the installation of the .NET Framework 3.5

During installation, you may encounter error 0x800f0906, 0x800f0907, 0x800f081f, or 0x800F0922, in which case refer to .NET Framework 3.5 installation error: 0x800f0906, 0x800f0907, or 0x800f081f to see how to resolve these issues.

If you still can't resolve your installation issue or you don't have an Internet connection, you can try installing it using your Windows installation media. For more information, see Deploy .NET Framework 3.5 by using Deployment Image Servicing and Management (DISM). If you're using Windows 7, Windows 8.1, the latest release Windows 10, or Windows 11, but you don't have the installation media, create an up-to-date installation media here: Create installation media for Windows. Additional information about Windows 11 and Windows 10 Features on Demand: Features on Demand.

Warning

If you're not relying on Windows Update as the source for installing .NET Framework 3.5, you must ensure to strictly use sources from the same corresponding Windows operating system version. Using sources from a different Windows operating system version will either install a mismatched version of .NET Framework 3.5 or cause the installation to fail, leaving the system in an unsupported and unserviceable state.

Collaborate with us on GitHub

The source for this content can be found on GitHub, where you can also create and review issues and pull requests. For more information, see our contributor guide.

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"This application could not be started" error when running a .NET Framework application

• Article
• 02/16/2023

In this article

When you attempt to run a .NET Framework application, you may receive the "This application could not be started" error message. When this error is caused by an installed version of .NET Framework not being detected, or by .NET Framework being corrupted, use this article to try to solve that problem.

If you still can't run the application after completing all the steps in this article, then the issue may be caused by some other reason, like a corrupted file system, missing dependencies, or a problem with the application. In that case, you can try contacting the app publisher or post a question to Microsoft Support Community or Microsoft Q&A for more help.

How to fix the error

To address this issue so that you can run your application, do the following:

1. Download the .NET Framework Repair Tool (NetFxRepairTool.exe). The tool runs automatically when the download completes.
2. If the .NET Framework Repair Tool recommends any additional action, such as those shown in the following figure, select Next.
   
3. The .NET Framework Repair Tools displays a dialog box shown in the following figure to indicate that changes are complete. Leave the dialog box open while you to try rerun your application. This should succeed if the .NET Framework Repair Tool has identified and corrected a corrupted .NET Framework installation.
   
4. If your application runs successfully, select the Finish button. Otherwise, select the Next button.
5. If you selected the Next button, the .NET Framework Repair Tool displays a dialog box like the following. Select the Finish button to send diagnostic information to Microsoft.
   
6. If you still cannot run the application, install the latest version of .NET Framework that's supported by your version of Windows, as shown in the following table. Windows version .NET Framework installation Windows 10 Anniversary Update and later versions .NET Framework 4.8 Runtime Windows 10, Windows 10 November Update .NET Framework 4.6.2 Windows 8.1 .NET Framework 4.8 Runtime Windows 8 .NET Framework 4.6.1 Windows 7 SP1 .NET Framework 4.8 Runtime Windows Vista SP2 .NET Framework 4.6 Note .NET Framework 4.8 is preinstalled on Windows 11 and Windows 10 May 2019 Update and later versions.
7. Attempt to launch the application.
8. In some cases, you may see a dialog box like the following, which asks you to install .NET Framework 3.5. Select Download and install this feature to install .NET Framework 3.5, then launch the application again.
   

See also

• .NET Framework System Requirements
• .NET Framework installation guide
• Troubleshoot blocked .NET Framework installations and uninstallations

Collaborate with us on GitHub

The source for this content can be found on GitHub, where you can also create and review issues and pull requests. For more information, see our contributor guide.