Use one of these to close Firefox if you are currently doing that by clicking the close X on the Firefox Title bar, especially if you have multiple windows or Private Browsing windows open to prevent losing tabs in unnoticed windows. *"3-bar" menu button -> Exit (Power button) *Windows: File -> Exit *Mac: Firefox -> Quit Firefox *Linux: File -> Quit ---- Make sure that you do not use Private Browsing mode. *https://support.mozilla.org/en-US/kb/private-browsing-use-firefox-without-history In case you use "Clear history when Firefox closes" or otherwise clear history. *do not clear the "Browsing history" *Settings -> Privacy & Security<br>Firefox will: "Use custom settings for history":<br>[X] "Clear history when Firefox closes" -> Settings *https://support.mozilla.org/en-US/kb/delete-browsing-search-download-history-firefox *using "Clear history when Firefox closes" in Firefox 102+ honors exceptions and keeps cookies with an allow exception, previous versions removed all cookies *clearing "Site settings" clears exceptions for cookies, images, pop-up windows, and software installation and exceptions for passwords and other website specific data