So, what I'm wanting to do is this:
I'm trying to copy my Dad's email archive, which currently exists in hundreds of Pegasus Mail folders, via IMAP, to a different server. My hope is to connect Thunderbird to the remote IMAP server, and to a newly-installed Mercury IMAP server sitting on top of this vast collection of Pegasus mail folders, and then manually drag the folders from one server to the other.
As I mentioned, I've freshly installed Mercury, installing only the IMAP component, and pointed it at the existing Pegasus mail C:\PMAIL\Public folder where his emails live. I got Thunderbird to connect to Mercury via IMAP, but then authentication failed. A little reading made me think I need to create a "local user" for authentication.
So I go to "Manage local users..." which pops up the dialog. I "Add" a new user, give it a valid username, a personal name, and a password, leaving APOP blank. When I hit "OK" from this dialog, the computer gives a little error noise, and no user ends up added. I've tried several different usernames and passwords, made sure the username is alphanum-no-spaces, personal name, no personal name, APOP, no APOP, nothing works. I simply can't add a local user and there's zero feedback as to what might be wrong.
One small clue is that at the top of the "Users defined for this system" dialog, it suspiciously says "Mailbox directory: ???" which makes me think something about the existing Pegasus Mail folders might be confusing it?
One other interesting point is that initially I -was- able to add a local user, which even successfully authenticated once via Thunderbird, but when I next launched Mercury, that user was gone and that's when I started not being able to create any more.
Any thoughts? Thanks in advance for any help y'all can give.
(Edited to add: Mercury 4.91.349; Windows 10 Pro 22H2)