Windows in S mode won’t let me install Waterfox
Windows in S mode does not allow installation of apps from outside of the Microsoft Store, so you will not be able to install Waterfox from Waterfox’s website. Although Waterfox is available from the Microsoft Store, it does not work on Windows in S mode and installation is currently disabled.
To install Waterfox, you must switch out of Windows S mode. To learn more, see the Windows 10 and Windows 11 in S mode FAQ at Microsoft Support.
Afterwards, visit Waterfox’s Waterfox download page or the Microsoft Store to install Waterfox. For more information, see How to install Waterfox on Windows and Download Waterfox on Windows from the Microsoft Store.