did you upgrade from an old version and skip V68.5?

Hello Matt I have not done updating as it happens automatically and this issue has only just started after moving house.\

Just undertake the procedure anyway. as it only resets all your stored passwords to blank.

I do not know what procedure you are talking about. I am running the latest edition. The password manager does not register my passwords or save them even though I have checked the box for it to do so.

In other words, install version 68, and go from there. Releases are found at http://archive.mozilla.org/pub/thunderbird/releases/