It seems that Session Buddy is an extension for Google Chrome. Do you mean the Session Manager extension for Firefox? https://addons.mozilla.org/firefox/addon/session-manager/ Either way, I'm not personally familiar with how these extensions work, sorry. ---- If you were working with Firefox's standard session files, this is a rough guide to what you might do: On the History menu, is "Restore Previous Session" grayed out or enabled? If it's enabled, and you have no currently open tabs you don't mind losing, give it a try to see whether that auto-restores your previous session. If it's grayed out, check the History menu for Recently Closed Windows and Recently Closed Tabs for missing pages. If there's nothing to restore, you can try to do a manual swap. The usual method is as follows (assuming Firefox is still running): (1) Open your current Firefox settings (AKA Firefox profile) folder using either * "3-bar" menu button > "?" button > Troubleshooting Information * (menu bar) Help > Troubleshooting Information * type or paste about:support in the address bar and press Enter In the first table on the page, click the "Show Folder" button. This should launch a new window listing various files and folders in Windows Explorer. (2) Scroll down and double-click into the '''sessionstore-backups''' folder. Save all files here to a safe location, such as your Documents folder. If not too much time has passed, you may be able to use one of them to recover your lost tabs. (3) Leaving that window open, switch back to Firefox and Exit, either: * "3-bar" menu button > "power" button * (menu bar) File > Exit Pause while Firefox finishes its cleanup -- these changes should occur: * recovery.js is moved from the sessionstore-backups folder to the main level of the profile folder and renamed to sessionstore.js * recovery.bak is deleted from sessionstore-backups (4) Once Firefox has stopped updating things, rename sessionstore.js to sessionstore.old (5) Copy in the file you want to restore (for example, an old previous.js or the file you discovered) and rename it to sessionstore.js -- Windows should show it right next to sessionstore.old in alphabetical order ''Note: the file name must be exact. By default, Windows hides the .js file extension. For best results in renaming files, I recommend showing all file extensions. See:'' http://windows.microsoft.com/en-us/windows/show-hide-file-name-extensions (6) Start Firefox and it should read sessionstore.js and restore whatever was in the substitute file; if you do not have Firefox set to restore your previous windows and tabs automatically, use History > Restore Previous Session But again, Session Manager might use different folders/file names.