It took all day
Okay, the long and the short of it is that every export option I tried to Powermail failed at some point or another. Exporting from Mail to Mailbox archives produced unreadable files in Powermail. Importing directly from Mail databases caused Powermail to stall on the first folder with subfolders of my clients and about 2300 messages. Nothing after my first folder would import after several tries.
I also found that the script I mentioned earlier failed to completely export subfolders from Entourage so that I was left not only with missing subfolders, but it failed to export a significant number of my 100 folders even at the top level.
Finally I just did it long hand. I dragged all my folders out of Entourage one by one, creating mbox files. (Note, you cannot drag parent folders and then expect the child folders to be included. You must drag the parent folders out separately and then also drag each child folder separately to create non-hierarchical mbox files.) I then renamed the files to remove the mbox visible name (that did not change the extension of the files). I then dragged the files into the Powermail folder window and had to approve each folder manually. I then organized these folders by dragging them into subfolders and thereby recreated my Entourage hierarchy of folders with some changes and updates to my existing system.
Checking my Postbox import that properly included all the folders from Apple Mail, I found that many of the messages were missing. So there seems to be some limitation either with Apple Mail or with the who import export system with a large number of emails that causes a problem for ANY program.
So it is now 10:40 pm and I have yet to start on any filters or rules to sort my incoming mail. I have not transferred my signatures. I have not set up any of my client or wife’s IMAP accounts, and I have yet to hear back from Powermail about the outgoing SMTP problem.
What a crazy way to live.