I believe this is a builtin feature that Firefox will also restore a pinned tab using the cache. It's a performance booster I believe and there doesn't appear to be a way around it. However, what you could do is simply clear the cache when Firefox closes. This would mean that Firefox can't restore the pinned tab from the cache because the cache doesn't exist. Then that should give you the behaviour that you are looking for. To do that, follow these steps: # Open the Firefox settings. # Click the '''Privacy & Security''' section on the left. # Scroll down to '''History'''. # If required, change the drop-down option to '''Use custom settings for history'''. # Check the '''Clear history when Firefox closes''' option. # Press the '''Settings...''' button. # Uncheck everything except for '''Cache'''. # Press '''Ok''' to save the change. Hope this helps.