Any idea what happen? Are you using a password manager other than what came with the browser?

Start Firefox using Troubleshoot(Safe) Mode {web link}

A small dialog should appear. Click Start In Troubleshoot(Safe) Mode (not Refresh). Is the problem still there?

Hi Folks

thanks for your response; I've actually restored most of the passwords manually - I'm not that good with IT and have no idea why the upgrade from Big Sur to Monterey should have destroyed the passwords in Firefox - the Safari ones were unaffected.

Once again, many thanks for your response.

Best wishes

Dave