You can backup your Firefox personal data locally. *https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles ---- You can backup certain files in the current profile folder with Firefox closed. You can use the button on the "Help -> More Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the <b>about:profiles</b> page. *Help -> More Troubleshooting Information -> Profile Folder/Directory:<br>Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder *https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data <hr> *bookmarks and history: places.sqlite *favicons: favicons.sqlite *bookmark backups: compressed .jsonlz4 JSON backups in the bookmarkbackups folder *cookies.sqlite for the Cookies *formhistory.sqlite for saved autocomplete Form Data *logins.json (encrypted logins;32+) and key4.db (decryption key;58+) for Passwords saved in the Password Manager<br>key3.db support ended in 73+; to use key3.db in 58-72, make sure to remove key4.db *cert9.db (58+) for (intermediate) certificates stored in the Certificate Manager *persdict.dat for words added to the spell checker dictionary *permissions.sqlite for Permissions and possibly content-prefs.sqlite for other website specific data (Site Preferences) *sessionstore.jsonlz4 for open tabs and pinned tabs (see also the sessionstore-backups folder)

Warning: Some system resets may allow you to save your data. But all programs and their data could be removed. Back up everything you don't want to lose to an external drive.