So a few weeks ago, I moved our online content to a new server, one with dual quad-core processors, 16GB RAM and a lot more bandwidth. One big change I made was to stop funneling messages through a third-party service and move everything in-house, so to speak, so we had full control.

Since all our email is uses the IMAP protocol, I simply had to move the messages from the old accounts to the new ones, after creating new accounts with the updated incoming and outgoing server information. It’s not an instantaneous process, but simple to do.

However, I have accumulated some 40,000 messages over the past decade. I’m not sure why I keep some of the older ones around, but nonetheless it took several hours for the task to complete.

Now some commercial email services can do this IMAP to IMAP transfer in the background, but I opted for the manual method rather than explore an automated alternative. I felt that just doing it was quicker than seeking out other solutions, but feel free to tell me your experiences in our Comments section.

In any case, things seemed to be working fine after the initial process of downloading the messages from our own server had finished. That is except for one thing, and therein lies a tale.

You see, suddenly my Inbox for tw0 of my email accounts began to spawn multiple Inboxes, in what appeared to be subfolders. It didn’t happen in the remaining accounts, for reasons I do not pretend to understand. However, I dutifully deleted the extraneous folders, only to find them returning whenever I relaunched Apple Mail.

So I began to search for solutions, and indeed there were several, but as you will learn shortly, not all proved successful and one was downright boneheaded.

First, it appeared there are two things in common for all or most of these cases. First, is that folks suffering from this anomalous email behavior are using a Leopard version of Mail. Second, the email server is using an open source application known as Courier IMAP.

Now if you have a Linux-based Web host that provides either cPanel or Parallels Plesk to manage your sites, you’ll find that Courier is part of the standard installation. So I rather suspect many of you might be vulnerable to this problem.

So let me tell the steps I followed to arrive at a solution.

In theory, when you delete an IMAP folder in Mail, it will delete the one on your mail server when the next connection is established. That happens every time Mail requests new messages, although you can use the Synchronize All Accounts function, in the Mail’s Mailbox menu, whenever you want to hasten the process.

Unfortunately, the problem wasn’t resolved. Next time Mail launched, the folders had returned, phoenix-like, in all their irritating glory.

My next step in resolving this dilemma was to login to our server, and attempt to manage the task remotely. I won’t detail the process here, as the location of your email fodlers will differ depending on which control panel your host is using, and, in the end, you may not even have access unless you have a VPS or dedicated server contract with them.

In any case, I deleted the extraneous folders on the server, but they returned as soon as Mail was launched from any of my Macs. Not good.

One wrong turn recommended by a certain well-known Mac troubleshooting site, in an article taking advice cribbed from Apple’s support forums, was to change the IMAP path prefix. This is a setting in Mail’s Advanced preference pane, under Accounts, that determines whether the extra folders in your account appear as subfolders in your Inbox or separately. If you have several email accounts in regular use, I suggest the latter.

If a path prefix is required, as it would be with a Courier IMAP setup, the path prefix would be created automatically by Mail when you set up the account. Removing it did nothing but turn my extra folders into subfolders under the Inbox. It didn’t eliminate the problem, and I didn’t expect it to. So I changed the setup back to its normal configuration, which, as I said, uses INBOX.

Now without belaboring the point, another suggestion calls for editing Mail’s preference file, the one in your Users / Library / Preferences folder, via Apple’s Property List Editor, which comes with the Apple Developer’s installation, or a third-party preference editor. It seems that a partly-corrupted preference file is supposed to be a major cause of this problem. But the solution seems a little extreme and, frankly, I felt I’d rather try other remedies first, and that leaves two.

The first is simply to trash the preference file, which removes all your accounts, other than the one for MobileMe, which is part of your default setting (assuming you are a member of MobileMe of course). That’s a fairly quick solution, particularly if you have only one or two accounts to recreate. Remember, too, that you don’t lose any of your messages, because you’re using IMAP. They’re stored on the server, not your Mac. Remember?

My solution was a little less draconian. I just deleted and recreated the actual accounts that were affected by this phenomenon after, of course, removing the errant folders. That proved to be the ideal solution — at least for me. Indeed, launching and relaunching Mail on my desktop and note-book Macs did not create any new problems.

So the case of the extra Inboxes was solved, at least for me. I suppose, in the scheme of things, it’s a minor problem and probably most who encounter it won’t care one way or the other if there’s an extra folder around. But that’s not me.

This article was posted on Monday, February 16th, 2009 at 6:30 PM and is filed under News and tagged with: Apple, Apple Mail, Bandwidth, Comments Section, Email, email accounts, Experiences, Folders, Inbox, Linux, Mail, Preference, Quad Core Processors, Third Party.