You can use Sync or copy the bookmarks from the Windows Firefox profile folder to the Ubuntu profile folder. It is not advised to share a profile between different OS. *https://support.mozilla.org/kb/Recovering+important+data+from+an+old+profile *http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox ----- You can copy files like these to the current Firefox profile folder to recover specific data. * bookmarks and history: places.sqlite * bookmark backups: JSON backups in the bookmarkbackups folder * SQLite files like cookies.sqlite (cookies) and formhistory.sqlite (saved form data) * logins.json and key3.db (decryption key) for Passwords saved in the Password Manager * cert8.db and possibly cert_override.txt for (intermediate) certificates stored in the Certificate Manager * persdict.dat for words you added to the spelling checker dictionary * permissions.sqlite and possibly content-prefs.sqlite for Permissions and Site Preferences * sessionstore.js for open tabs and pinned tabs and tab groups