This obviously comes too late, but, don't exit Firefox! Or if you already did, don't start it back up again! Ahem. Let's see what we can still salvage. ''If Firefox is running:'' Open your current Firefox settings (AKA Firefox profile) folder using either * "3-bar" menu button > "?" button > Troubleshooting Information * Help menu > Troubleshooting Information In the first table on the page, click the "Show Folder" button. This should launch a new window listed various files and folders. For best results, change the view to "Details". (''If Firefox not running, get to this folder by pasting the following in the Run box on the start menu and pressing Enter: %APPDATA%\Mozilla\Firefox\Profiles and then double-click into the most recently updated semi-randomly-named folder you find there.'') (1) Scroll down and double-click into the '''sessionstore-backups''' folder. Copy all files here to a safe location such as your Documents folder. (2) Go back up to the main level and scroll down to the sessionstore file(s). sessionstore.js usually contains your session data as of the last time Firefox exited normally. This does not exist while Firefox is running. Go ahead and copy any files whose names start with sessionstore and which have dates in a relevant range to a safe location such as your Documents folder. ---- By default, Windows hides the .js extension. To work with files most accurately, you may want to turn off that feature. This article has the steps: http://windows.microsoft.com/en-us/windows/show-hide-file-name-extensions The kinds of files you may find among your sessionstore files are: * sessionstore.js: the windows and tabs from your previous Firefox session (created when Firefox closes, removed after Firefox reads it at startup) * recovery.js: the windows and tabs in your currently live Firefox session * recovery.bak: a backup copy of recovery.js * previous.js: the windows and tabs in your last Firefox session, after Firefox starts; sessionstore.bak for pre-33 versions of Firefox * upgrade.js-''build_id'': the windows and tabs in the Firefox session that was live at the time of your last update; sessionstore.bak-''datetime'' for pre-33 versions of Firefox Find anything that looks useful?