Hello lovelyday_786, Would you try this please : Type in the address bar '''about:config''' and press Enter (promise to be careful, if asked) Type in the search bar and look for the preference : '''browser.sessionhistory.max_entries''' And set the value to one that's lower than 50 (= default). Then close and restart firefox. ------------------------------------------------------------------------------------------------<BR> Maybe you'd also like to take a look at this article : https://www.davidtan.org/tips-reduce-firefox-memory-cache-usage/

Current value at my machine is at 10 but still Browser keeps the records of 50 backspace (go back) history. Restarted the Firefox and Computer both but no effect.