Have you tried copying the old profile folder to somewhere on the new HDD (for example into: %appdata%\Mozilla\Firefox\Profiles) Then using the Firefox Profile Manager to create a new profile, setting this new profile's folder location to the folder that you just copied? (for example: %appdata%\Mozilla\Firefox\Profiles\whatever_the_old_folder_is_called)

If you are unfamiliar with using the Firefox Profile Manager, see here: https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

I believe you will need to create a new profile. You can do that with Firefox open or closed.

https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles#w_start-the-profile-manager-when-firefox-is-closed https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data#w_what-information-is-stored-in-my-profile

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.

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 about:profiles page (Root directory).

• Help -> More Troubleshooting Information -> Profile Folder/Directory:
  Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder
• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

• 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)

Thanks so much for your responses! I finally just copies over the relevent files for password and bookmarks. Phew! Not all the bookmarks came over for some reason. I just copied over the key4 and json and seemed only to get the "recently bookmarked". Does that make sense?

For passwords: logins.json and key4.db are both needed. Sounds like this worked

For bookmarks, two choices:

(1) Bookmark and history data is stored in two files, places.sqlite and favicons.sqlite. If you transferred those, you should have everything.

(2) Automatic bookmarks backups are stored in the bookmarkbackups folder in compressed (.jsonlz4) files. If you transferred those, you need to restore one of them. See: Restore bookmarks from backup or move them to another computer.

Note that you can find all bookmarks and history in the Library (Ctrl+Shift+O). Some drop-down lists only show recent bookmarked pages and recent history, so do not get confused.

Did the favicons but I don't see that it did anything. Anyway, bookmarks are really unimportant and recreate-able. I do love that documentation for Firefox seems to be in human brains, unlike when I wrote software and we documented things in the code and in printed English. This works, so thank you all.