Open YouTube in a Private Window . If the plugin works there, a different extension is likely causing a conflict in your main session. 2. Proven Extensions (Still Working in 2026)
The recent instability in Firefox playlist downloaders isn't just bad luck; it’s the result of YouTube’s aggressive implementation of logic and server-side request throttling . By constantly shifting the CSS selectors and encryption keys (the "signature") required to pull media streams, YouTube has effectively turned these plugins into a race against obsolescence. When your favorite Firefox add-on stops working, it’s usually because the developer hasn't yet reverse-engineered the latest daily patch from Google. The "Fix" is a Shift in Philosophy