In certain versions of Windows 10, you may receive a notification when you run the Firefox installer with a warning about Microsoft-verified apps.
This message is displayed because Firefox is not in the Microsoft store. Any copy of Firefox downloaded from www.mozilla.org is safe to install, so choose "Install anyway".
If you do not see the option to “Install anyway”, follow the steps below to change your system settings.
- Open the Windows 10 start menu and select Settings.
- Click on Apps in the settings menu.
- Under the Choose where to get apps section, click on the dropdown menu and select one of the options that allows you to install from Anywhere.