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Migrating profiles from Time Machine backup, Firefox 70.X–Firefox 95

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  • Last reply by cor-el

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Hello, I am migrating profiles from a Time Machine backup of my mid-2012 Mac, which was running Yosemite, with Firefox 70-something, to my new M1 Mac, which is running Monterey, with Firefox 95.

I read an article which said I should copy ALL of the files inside my old profiles folder to the new folder and replace the new files. I did this, and my bookmarks and passwords showed up. However, now the type is about 1 pt. in size and everything within my window only reaches about half the width across.

I think what happened is that I copied over a file that deals with the size and display of text vs. resolution that was set for the old Mac.

My questions are: 1) What might the name of that profile file be? 2) Am I able to delete just that one file and things will display correctly? Or, 3) Do I need to do a re-install of version 95 and then only copy over bookmarks and password files?

Hello, I am migrating profiles from a Time Machine backup of my mid-2012 Mac, which was running Yosemite, with Firefox 70-something, to my new M1 Mac, which is running Monterey, with Firefox 95. I read an article which said I should copy ALL of the files inside my old profiles folder to the new folder and replace the new files. I did this, and my bookmarks and passwords showed up. However, now the type is about 1 pt. in size and everything within my window only reaches about half the width across. I think what happened is that I copied over a file that deals with the size and display of text vs. resolution that was set for the old Mac. My questions are: 1) What might the name of that profile file be? 2) Am I able to delete just that one file and things will display correctly? Or, 3) Do I need to do a re-install of version 95 and then only copy over bookmarks and password files?
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You can copy certain files with Firefox closed to the current profile folder to transfer or recover personal data. Note that best is to avoid copying a full profile folder.


  • 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
    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)