Restore previous session
I had to update firefox. So I closed the five windows I had open then updated. When I re-opened firefox only 3 windows re-opened. How can I restore the other windows?
All Replies (2)
The number of windows to restore is controlled by the browser.sessionstore.max_windows_undo preference in about:config.
Note that if you leave all windows open that there is no real limit because the complete session should be restored. Only when you close tabs and windows there is a limit on how many tabs (25) and windows (3) you can reopen when the session is restored on the next start.
Firefox also creates upgrade.jsonlz4-<build_id> files during an upgrade of Firefox in the sessionstore-backups folder.