I setup this mail server a few days ago according to this tutorial, worked fantastic:
http://www.pixelinx.com/2010/10/creating-a-mail-server-on-ubuntu-using-postfix-courier-ssltls-spamassassin-clamav-and-amavis/
After noting that all the tutorials seem to have a different way of adding IMAP folders, I decided to foolishly go ahead and edit:
/var/mail/virtual/mywebsite/myaccount/courierimapsubscribed
adding in some extra IMAP folders in to that file, which sure enough now show up in the IMAP server selected folders in thunderbird, but failed with folder doesn't exist error.
Little did I notice I should have been using "ls -a", and there are:
.Inbox
.Sent
.Trash
folders, which each have a number of files and folders in them:
courierimapacl courierimapkeywords courierimapuiddb cur maildirfolder new tmp
From the tutorial at the top, I can see that these files and folders were automatically created somehow, so I presume there is a courier or postfix command to create IMAP folders the proper way. So how do I add IMAP folders with the above set-up?