Firefox – All tabs groups lost after updating to Firefox 57.0 Quantum

Firefox 3 stores its session data in a JavaScript file located in the user profile folder. To restore an accidentally discarded session, simply:

1. Quit Firefox.
2. Replace the current JavaScript file with the backed-up version.
3. Restart Firefox.

—Jesse Kirdahy-Scalia (13 September 2009). "Restore a Lost or Discarded Firefox Session in Three Quick Steps". Open Media Boston. Media Working Group, Inc.

The solution to disable automatic updates without running Firefox is as follows (OS is Windows):

• Edit the file prefs.js, located in %APPDATA%\Mozilla\Firefox\Profiles\xyz.default\ which usually translates to C:\Users\username\AppData\Roaming\Mozilla\Firefox\Profiles\xyz.default\ (Note: username and xyz will vary)
• Make sure the line user_pref("app.update.enabled", false); is present in the file; if it isn't, add it or modify it. Ignore the warning that this file should not be edited
• Save and close the file
• Start and use Firefox without having to worry about automatic updates
• Optional: Note the button "Check for updates" in the "About Firefox" dialog box. Of course, DO NOT click it until you are prepared and ready to receive the update