One or more master keys need a password. Set the password

Operating system

Windows

Joplin version

3.3.13

Desktop version info

3.3.13

Sync target

Dropbox

What issue do you have?

I am migrating from an old Windows 10 PC to a new Windows 11 PC.
The new PC has all of the Joplin files in the same location as the old one.
I then installed Joplin 3.3.13 for Windows.
Upon running it, the notorious warning quoted in the title of this post appears.
Because of previous problems, I have not (knowingly) encrypted anything.
I can still read the text of items in my Joplin folder on Dropbox.
What did I do wrong (or what did I fail to do that I should have)?
How can I correct this situation?

P.S. After upgrading to 3.4.12, the problem persists.