Fix: “Platform Version Is Not Compatible with minVersion” in Firefox

After updating Mozilla Firefox, you may encounter the error: “Platform version is not compatible with minVersion.” This typically occurs when the update process fails to complete properly, leading to mismatched version references between the update configuration files and the actual Firefox executable.

This issue isn’t tied to a specific build—it has been reported across various versions, including 94.0.2, 63.0.3, 120.0.1, and others. Fortunately, it’s a fixable problem. The solutions below will guide you through resolving it and restoring Firefox to working condition.

1. Temporarily Disable Antivirus During Installation

If reinstalling or updating Mozilla Firefox results in the “Platform version is not compatible with minVersion” error, your Windows Security settings or third-party antivirus software may be interfering with the installation process. These security tools can block or quarantine essential Firefox files during installation or updates. To avoid this, temporarily disable Windows Security before reinstalling Firefox.

1. In the Windows search bar, type “Windows Security” and open the app.
2. Click on “Virus & Threat Protection” in the left sidebar.
3. Under “Virus & Threat Protection Settings,” click “Manage Settings”.
4. Toggle the “Real-time protection” switch to Off (Windows will warn this isn’t recommended).
5. Install Mozilla Firefox, then immediately re-enable real-time protection by toggling the switch back to ON.

2. Reinstall Mozilla Firefox Without Uninstalling

Reinstalling Firefox over the existing installation can replace corrupted or mismatched files caused by an incomplete update—without deleting your personal data. This method retains your bookmarks, browsing history, passwords, and other profile settings, making it a safe way to repair the browser.

1. Visit the official Mozilla download page: https://www.mozilla.org/en-US/firefox/all/#product-desktop-release
   
2. Select and download the latest version for your operating system.
3. Locate the downloaded file (typically in your Downloads folder).
4. Double-click to launch the installer
5. Follow the on-screen instructions to complete the installation

3. Perform a Clean Installation of Mozilla Firefox (Only if Necessary)

If reinstalling Firefox without uninstalling didn’t fix the issue, you may need to perform a clean installation. This will completely remove all corrupted files and user data, giving you a fresh, working copy of Firefox.

Note: This process will delete your bookmarks, history, saved logins, and settings unless you back them up first.

1. In the Windows search bar, type “Add or remove programs” and open the matching system settings.
2. Locate Mozilla Firefox in the programs list and click Uninstall to remove it.
   
3. Manually delete remaining files:
   • 64-bit Windows: Go to C:\Program Files\Mozilla Firefox
   • 32-bit Windows: Go to C:\Program Files (x86)\Mozilla Firefox
   • Delete the entire Mozilla Firefox folder

   

4. Download a fresh copy from the official Firefox website and install. Tip: Temporarily disable antivirus if installation fails.