I think you have already ask this question here ;) https://support.mozilla.org/de/questions/984007?esab=a&s=&r=3&as=s Cleaning your History and Cache: #Go to Firefox > History > Clear recent history or (if no Firefox button is shown) go to Tools > Clear recent history. #Under "Time range to clear", select "Everything". #Now, click the arrow next to Details to toggle the Details list active. #From the details list, check ''Cache'' and ''Cookies'' and uncheck everything else. #Now click the ''Clear now'' button.