How to Fix the 'Unknown Publisher' Warning When Installing a Cumulative Update on Windows 11 Pro

When installing a cumulative update on Windows 11 Pro, you may encounter a warning message that says 'Unknown Publisher.' This warning is displayed when the operating system cannot verify the authenticity of the update. While it is important to be cautious when installing software from unknown sources, in this case, the warning is related to a legitimate update from Microsoft. In this article, we will guide you through the steps to fix the 'Unknown Publisher' warning and successfully install the cumulative update on your Windows 11 Pro system.

Step 1: Check Windows Update Settings

The first step is to ensure that your Windows Update settings are configured correctly. Follow these steps:

1. Click on the Start button and select Settings (the gear icon).
2. In the Settings window, click on Windows Update in the left sidebar.
3. Make sure that the Windows Update toggle switch is turned on. If it is off, click on it to enable Windows Update.
4. Scroll down and click on Advanced options.
5. In the Advanced options window, make sure that the Receive updates for other Microsoft products when you update Windows toggle switch is turned on.
6. Close the Settings window.

Step 2: Disable SmartScreen Filter

Windows 11 Pro includes a feature called SmartScreen Filter, which helps protect your system from malicious software. However, sometimes it may mistakenly flag legitimate updates as potentially harmful. To disable SmartScreen Filter temporarily, follow these steps:

1. Open File Explorer by pressing Win + E on your keyboard.
2. Navigate to the location where you saved the cumulative update file.
3. Right-click on the update file and select Properties.
4. In the Properties window, click on the General tab.
5. At the bottom of the window, you will see a section labeled Security. Click on the Unblock button.
6. Click OK to close the Properties window.

Step 3: Install the Cumulative Update

Now that you have adjusted the necessary settings, you can proceed with installing the cumulative update. Follow these steps:

1. Double-click on the cumulative update file to start the installation.
2. If prompted by User Account Control (UAC), click Yes to allow the installation.
3. Follow the on-screen instructions to complete the installation process.
4. Once the installation is finished, restart your computer if prompted.

After restarting your computer, the 'Unknown Publisher' warning should no longer appear, and the cumulative update will be successfully installed on your Windows 11 Pro system.

The 'Unknown Publisher' warning when installing a cumulative update on Windows 11 Pro can be resolved by adjusting the Windows Update settings and temporarily disabling the SmartScreen Filter. By following the steps outlined in this article, you can ensure a smooth installation process and keep your system up to date with the latest updates from Microsoft.