.Net Strongname Sn.exe

Troubleshooting the Access Denied Error with sn.exe

When working with .NET assemblies, signing them securely with a strong name is crucial for maintaining the integrity and uniqueness of your libraries. However, many developers encounter the frustrating Access is Denied error when attempting to create a new key using the Strong Name Tool (sn.exe). This error can be particularly perplexing when the same operation works seamlessly on older operating systems like Windows XP, but fails on newer platforms such as Windows Vista.

In this blog post, we’ll help you understand the causes of the Access Denied error and provide a comprehensive solution so you can get back to developing without interruptions.

Understanding the Error

When you run a command like the following in your command prompt or PowerShell:

sn -k keypair.snk

You might encounter the error:

Failed to generate a strong name key pair -- Access is denied.

This indicates that the tool is unable to create the necessary key pair due to restrictions imposed by your user account or file permissions.

Common Causes

  1. User Access Control (UAC): Windows Vista introduced UAC which enforces stricter control over what operations a user can perform, especially regarding administrative tasks.
  2. File Permissions: The key container where the keys are stored may lack the necessary permissions for your user account.

Solutions to Fix the Access Denied Error

To resolve this issue, follow these steps:

1. Check User Account Permissions

Make sure your user account has access to the key container directory. The keys are typically stored in:

C:\Documents and Settings\All Users\Application Data\Microsoft\Crypto\RSA\MachineKeys

Granting Permissions

  • Navigate to the folder outlined above.
  • Right-click on the MachineKeys folder and select Properties.
  • Under the Security tab, check if your user account is listed.
  • If it isn’t, click on Edit to add your user account and ensure you grant at least Read and Write permissions.

2. Run Command Prompt as Administrator

While you mentioned attempting to run PowerShell and the command prompt as Administrator, ensure you are doing it correctly:

  • Right-click on the Command Prompt (or PowerShell) and select Run as administrator.
  • This step might seem trivial, but it’s crucial for permissions relating to creating keypairs.

3. Temporary Disable User Access Control (UAC)

As a last resort, if the above steps fail, you may temporarily disable UAC to test if it’s the cause of the problem:

  1. Open the Control Panel.
  2. Click on User Accounts.
  3. Select Change User Account Control settings.
  4. Move the slider down to Never notify and click OK.
  5. Restart your system and attempt to run the sn.exe command again.

Note: Disabling UAC can expose your computer to unnecessary risks. Make sure to re-enable it after completing your task.

Conclusion

If you’re encountering the Access Denied error code while using sn.exe for signing .NET assemblies, don’t be disheartened. By following the steps listed above, you can regain access and create your strong name key pairs successfully. Always remember to check user permissions and be aware of the implications of running your applications with elevated privileges.

Happy coding! If you have any other questions or run into more issues, feel free to reach out in the comments below.