zefir_zwiejek said I have several hundred tabs, tick them all and want to bookmark them, but that never works. I'm not sure what "tick them all" refers to. There's no built-in way to bookmark all open tabs across all windows at once, but Firefox does have a feature to bookmark all of the tabs in the current window to a new folder. The shortcut is Ctrl+Shift+D, or you can find it on classic Bookmarks menu on the optional menu bar optional Bookmarks menu button for the main toolbar Does that feature work? If not, is there any error message? Are you still able to add one bookmarks manually, for example by clicking the star icon in the address bar? If that doesn't work, it can indicate a database problem (more details if needed). I will also add that the "Settings" menu does not open! Settings, formerly called Options, should open an internal page in a new tab. If you type or paste the address about:preferences into the address bar and press Enter, can Firefox show the page? ==Ctrl+Shift+D = NOT WORK / NOR REACTION / NO MESSAGE ERROR /NOTHING HAPPEN This marks 1000 Tabs, but nothing else can be done, no reaction, no error, no message, I don't know how to write or add 1000 tabs to the bookmarks, I asked a many developers, for 3 years and no one can help, I tried 100 different ways and there's nothing I can do, do I really need to lose my data? "Reset firefox completely" = data loss Even moving the profile and trying to restore it always ends with the same problem, still nothing works, how to save all 1000 tabs to a text file, even the best of the best ways fails, because after saving it is 0KB, no data !!!