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Import Data from older Version

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My system broke during an update. Now I want to import my old Firefox userdata, but everytime I try to use the old data firefox just forces the creation of a new profile?

Is it completely impossible to recover data not created with the same firefox version?

My system broke during an update. Now I want to import my old Firefox userdata, but everytime I try to use the old data firefox just forces the creation of a new profile? Is it completely impossible to recover data not created with the same firefox version?

Réiteach roghnaithe

A profile needs to be registered in profiles.ini to make Firefox use a copied profile.

Note that some versions like Snap use a different location for profiles.

You can use the button on the "Help -> More Troubleshooting Information" (about:support) to go to the current Firefox profile folder or use the about:profiles page (Root directory).


You can copy certain files with Firefox closed from one profile folder to the current profile folder to transfer personal data. Note that best is to avoid restoring a full profile folder and only restore important files that are safe to restore/transfer.


  • 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) and key4.db (encryption key/primary password) for logins saved in the Password Manager
  • cert9.db for 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)
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If that's the case: Can I somehow find out with which version the data was created and just install that version of Firefox?

Helpful?

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Réiteach Roghnaithe

A profile needs to be registered in profiles.ini to make Firefox use a copied profile.

Note that some versions like Snap use a different location for profiles.

You can use the button on the "Help -> More Troubleshooting Information" (about:support) to go to the current Firefox profile folder or use the about:profiles page (Root directory).


You can copy certain files with Firefox closed from one profile folder to the current profile folder to transfer personal data. Note that best is to avoid restoring a full profile folder and only restore important files that are safe to restore/transfer.


  • 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) and key4.db (encryption key/primary password) for logins saved in the Password Manager
  • cert9.db for 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)

Helpful?

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Okay, with that confirmation I tried again with a different process: New profile delete all files in there copy in the safe files select that (incomplete profile)

This works.

Previously when I saw these instruction I tried to insert the files into a complete profile. Which caused the same error as just using all files from the old profile.

Helpful?

Cuir ceist

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