Probably nothing you can do about that to totaly get back what was lost. You can look through the History in the Library and may be able to search for and find things you remember or things from the Today |Yesterday |Last seven days | folders. You can look at sessionstore files, these contain the information, #Rename them for instance add .old1, old2 etc so you preserve anything you have #Then delete the sessionstore.js #Now try in turn copying each one so that it overwrites and is renamed as the current file sessionstore.js . Obviously you must do this whilst Firefox is closed and then restart for each renamed file. * Find the profile from an open Firefox (I am not sure of exact wording and options)<br />Help -> Troubleshooting -> |Pofile: Open Folder [] | <br /> see [[Profiles - Where Firefox stores your bookmarks, passwords and other user data]] * You are likely to have the current file ''sessionstore.js'' , the last one sessionstore.bak then may have numbered files. **Possibly see also<br />http://kb.mozillazine.org/Sessionstore.js <br /> [[Restore previous session - Configure when Firefox shows your most recent tabs and windows]]<br /> and for full techi details https://wiki.mozilla.org/Session_Restore In future note bookmarks are more robust than history or session information so if something is important please consider bookmarking it.