Ignore me. Showing hidden files has found my logins.json file. Attempting to restore – but seriously not impressed if a firefox update (and the syncing) has stuff things! Not simple to actually offer 'old profiles' so about:profiles offers some back-tracking??

Note that you also need key4.db as this file stores the encryption key.

Thanks. I found the two files and replaced the 'recent' versions. Didn't work, but I'll try again with a file from further back. See where we get to :O)

Did you ever sync on your iPhone? Just wonder if this bug is the problem. https://bugzilla.mozilla.org/show_bug.cgi?id=1872730

Not on my phone at all – only got firefox on my macbook and iMac. I copied two files from time machine back off a month ago but did nothing. I'll have one more go (with oldest time machine I can find) then accept my fate. Thanks.

Do you at least see logins in logins.json if you open this file in a Firefox tab?

• https://firefox-source-docs.mozilla.org/devtools-user/json_viewer/

If that shows logins, but you do not see them in about:logins then this means that key4.db is damaged or doesn't match (i.e. doesn't have the right encryption key). If you haven't changed the PP overtime or have never used it, then an older copy of key4.db might work as well with a later logins.json that has the latest passwords.

Thanks. I'll try that (slight delay as work deadline)