When your users see the message "Publisher: Unknown Publisher" during the installation of your Windows application, it indicates that the installer lacks a valid digital signature or that the signature is not recognized by the operating system as trusted. To resolve this issue and provide a more trustworthy installation experience, you need to sign your application setup with a valid digital signature. Here's a step-by-step guide:
Step 1: Acquire a Code Signing Certificate
- Purchase a Code Signing Certificate: Acquire a code signing certificate from a trusted Certificate Authority (CA). Popular CAs include DigiCert, Sectigo, and GlobalSign. You can usually purchase a code signing certificate directly from their websites.
Step 2: Sign Your Application
Once you have obtained a code signing certificate, follow these steps to sign your application:
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Open Visual Studio: Open your Visual Studio 2015 project.
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Configure Signing:
- Right-click on your project in Solution Explorer.
- Select "Properties."
- Go to the "Signing" tab.
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Select the Certificate:
- Check the box for "Sign the ClickOnce manifests."
- Choose the certificate you obtained from the drop-down list or use the "Select from File..." option to locate your certificate.
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Build and Publish:
- Rebuild your project.
- Publish your application.
Step 3: Verify the Digital Signature
After signing your application, it's crucial to verify the digital signature:
- Check Digital Signature:
- Right-click on the installer file (e.g., setup.exe).
- Select "Properties."
- Go to the "Digital Signatures" tab.
- Verify that the digital signature is present and is issued by the correct publisher (your organization).
Step 4: Distribute the Installer
Distribute the signed installer to your users. When they run the setup, they should no longer see the "Unknown Publisher" warning if the digital signature is valid and the certificate is recognized.
Additional Tips:
- Ensure that the system time on the signing machine and the user's machine is correct. Code signing certificates have a validity period, and incorrect system time may lead to verification issues.
- Keep your code signing certificate private and secure.
- Renew your code signing certificate before it expires to ensure a smooth installation experience for your users.
By following these steps, you can sign your Windows application setup and address the "Unknown Publisher" issue during installation. This enhances the trustworthiness of your application and helps users feel more confident in installing it on their systems.
