Make sure Firefox isn't set to run in permanent Private Browsing mode (Always use Private Browsing mode; Never Remember History). *https://support.mozilla.org/en-US/kb/private-browsing-use-firefox-without-history *https://support.mozilla.org/en-US/kb/common-myths-about-private-browsing *Settings -> Privacy & Security<br>Firefox will: "Use custom settings for history" *remove checkmark: [ ] "Always use Private Browsing mode" Pinned tabs are saved as part of session data in sessionstore.jsonlz4. *https://support.mozilla.org/en-US/kb/restore-previous-session 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