If this is a computer managed by an IT department, then that message wouldn't be unusual and might not be possible to turn off. On a home computer, this message usually appears after certain third party security software inserts changes to Firefox. Let's see whether we can track it down. On the Settings page, where you see the message, can you click the message to view the About Policies page? If not, type or paste '''about:policies''' in the address bar and press Enter to load the page. Normally, the Active panel says "The Enterprise Policies service is inactive." What does yours list? (You can ignore the Documentation list unless you're curious about all the different possible policies. This list doesn't indicate which ones are actually active in your Firefox.)