Hi, you should always do this, make a backup :

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

Pkshadow said

Hi, you should always do this, make a backup :

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

I've tried that, still didn't work.

You need logins.json and key4.db to transfer login data from a Firefox 58+ profile.

You can copy files like these with Firefox closed to the current profile folder to recover specific data.

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

• bookmarks and history: places.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 (passwords) and key4.db (58+) or key3.db (57 and older) (decryption key) for Passwords saved in the Password Manager
  if you only have key3.db then make sure to remove an existing key4.db
• cert9.db (58+) or cert8.db (57 and older) for (intermediate) certificates stored in the Certificate Manager
  if you only have cert8.db then make sure to remove an existing cert9.db
• persdict.dat for words you added to the spelling 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)

cor-el said

You need logins.json and key4.db to transfer login data from a Firefox 58+ profile.

---

You can copy files like these with Firefox closed to the current profile folder to recover specific data.

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

• bookmarks and history: places.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 (passwords) and key4.db (58+) or key3.db (57 and older) (decryption key) for Passwords saved in the Password Manager
  if you only have key3.db then make sure to remove an existing key4.db
• cert9.db (58+) or cert8.db (57 and older) for (intermediate) certificates stored in the Certificate Manager
  if you only have cert8.db then make sure to remove an existing cert9.db
• persdict.dat for words you added to the spelling 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)

Tried it, nothing happened. All my bookmarks and settings are there. But my saved logins are not. Maybe it's a bug with Linux?

Are you using the Firefox version from the repositories of your Linux distribution or the Firefox version from the official Mozilla server?

I installed it from the linux terminal. Should I try getting it from the actual Firefox website?

Try the Firefox version from the Mozilla server to see if that still has the same problem.

• https://www.mozilla.org/en-US/firefox/all/

Weird thing happened, so I added everything from my profile, turns out that was the issue. When I just added the login.json and key3.db everything was there.

I had the same problem and noticed exactly the same thing, copying a Firefox 61 from Windows to Debian-based Linux Mint.

If I copy the whole profile, the saved passwords were missing. If I created a new profile and just copied key4.db and login.json the saved passwords appeared.

After some experimentation it turned out that the culprit was pkcs11.txt. I am not sure exactly what this file contains but deleting it solved the problem, enabling me to copy the entire profile to the new computer and retain all my data, saved passwords and everything.

pkcs11.txt has replaced secmode.db. This new file is a text file and can contain ans absolute path to some security device settings. You can open this file in a text editor to check its content in case you are curious.

The presence of specific files that contain file paths is one of the main reasons that you should never copy the full contents of profile folder to another profile folder. If both profiles exist and can be accessed then the original profile might be used and if not then the behavior of the profile can be erratic and some things might not work properly. Therefor I always recommend to only copy specific data files that you need. Even prefs.js can contain file paths that are platform specific and you need to check such files and edit out these specific lines or better omit this file and redo the profile setup.

Thanks cor-el that's really useful.