What is .NET Framework?

The .NET Framework is a software framework developed by Microsoft, containing a rich set of programming libraries and runtime environments to support the operation of Windows applications. It plays a crucial role within the system, as many Windows applications rely on the .NET Framework to function properly.

Why Does Lets VPN Depend on .NET Framework?

The Windows version of Lets VPN is developed using C# technology, requiring .NET Framework as its foundational runtime environment. This framework provides essential support for stable application performance, including deep system compatibility, network communication handling, and interface rendering. If issues arise with .NET Framework, Lets VPN will be unable to function properly.

 

Scenarios When .NET Framework Fails to Run

Scenario 1: Error During Lets VPN Installation

During the installation process of Lets VPN, the software will automatically attempt to update and verify the integrity of .NET Framework to ensure it is in a usable state. If the verification fails, an error message will be displayed, halting the installation process. The error prompt appears as follows:

Scenario 2: Lets VPN Fails to Respond on Startup

Occasionally, due to Windows system updates or other factors, .NET Framework may become unintentionally corrupted. In this situation, even if Lets VPN has been successfully installed, it may fail to start properly because of issues with .NET Framework.

How to Fix .NET Framework Failure Issues?

If issues arise with .NET Framework, try the following three methods to repair it:

 

Method 1: Manually Update .NET Framework to the Latest Version

Manually check for and install the latest version of .NET Framework to repair any potential corruption issues and ensure its proper functionality. Follow these steps:

  1. Open Command Prompt:

    • Press Windows + R keys, type cmd, and then press Enter.

  2. Enter the following command to check the .NET Framework version:
    ​reg query "HKLM\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full" /v Version

  3. Check the output to confirm the current version (the latest version is 4.8.1).

  • If the version is lower than 4.8.0, please refer to the next steps for updates.

  • If it is already version 4.8.0 or 4.8.1, please refer to other methods.

4. Visit the Microsoft .NET Framework download page in your browser.

  • Download .NET Framework 4.8.0 | Free official downloads

  • Download .NET Framework 4.8.1 | Free official downloads

5. Click Download .NET Framework Runtime and install it manually.

  • Due to system compatibility issues, it is recommended that you install version 4.8.0 first.

  • If the problem is still not solved, you can try to upgrade to version 4.8.1.

6. After a successful installation, restart your computer and check if Lets VPN runs correctly.

Method 2: Repair .NET Framework Using the System Command sfc /scannow

The sfc /scannow command is a built-in Windows system repair tool that can safely scan and automatically fix corrupted system files, including those related to .NET Framework, to ensure stable system operation. Follow these steps:

  1. Open Command Prompt:

    • Press Windows + R keys, type cmd, and then press Enter.

  2. In the Command Prompt window, enter the following command:
    ​sfc /scannow

  3. Wait for the system to complete the file scan and repair process.

  4. Restart your computer and check if Lets VPN can now run properly.

Method 3: Repairing the System Using Third-Party Security Software

In Windows systems, third-party security tools can be utilized to detect and repair system issues, including potential problems with the .NET Framework.

 

Taking 360 Total Security as an example, here’s how to perform a system repair：
​(If you’re using other tools, please refer to their respective help resources or contact their customer support for assistance.)

If none of the above methods resolve the issue, please feel free to contact our online customer service in the bottom right corner. Our professional technical team will be available to provide one-on-one remote support to help you troubleshoot and resolve any related issues.

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