There I was, ready to impress my new IT clients with how easy Outlook 2011 makes it to create mbox folders to import into Mail. Simply drag a folder to the Yosemite Desktop. What the heck? Did Outlook just rubber-band me? It did it again! Well, of all the...It worked before. On the other hand, dragging single and multiple messages to the desktop to produce individual EML files--which Mail doesn't understand--worked just fine. How nice.

After wasting several minutes explaining to my clients how this method really did work once upon a time, I went to plan B. Alas, since I'd only allotted time for plan A, plan B involved forking over $30 for dedicated Outlook email export software. It was worth it under the circumstances, but if I'd done my homework, and left myself a bit more time, plan B would've been one of the methods below.

Note: Microsoft was unable to confirm the exact reasons for this issue, but drag-to-mbox still works under 10.9.5, so if you want to move to Mail, you might want to do it before upgrading from Mavericks to Yosemite. If that's still an option...

The IMAP connection

If you're using IMAP, or Exchange for that matter, you can skip the rest of this article. Your email is tucked away online and all you need to do with Mail is create your new local account using the IMAP or Exchange option. That account will populate as quickly as the speed of your Internet connection allows. Painless, easy. Move on. Nothing to see here...

Likewise, if you're a POP user, but are willing to switch to IMAP, your transfer solution is nearly as simple. While you're at it, you might consider a permanent switch to IMAP if your provider offers it--it has its advantages, even if you have to pay for it. Just sayin'.

While this modus operandi can be used with any email client, these are the steps for Outlook 2011.

1. Open Outlook 2011 and back up your email--you never know. Head to File > Export and choose to export as Outlook for Mac Data File (.olm).

2. Create the IMAP account using your provider's settings and name the top-level folder "New IMAP Account", or some such. If you're provider doesn't support IMAP, use your existing Google account or open a new one. It's free and features a healthy 15GB of space (shared with Google docs and photos)

3. Drag the email and folders from the pop account's folder to the new IMAP account folder.

4. Be patient. It will take a while for all the old email to propagate to the server online.

5. Open Mac Mail and create the new account with the IMAP option. Mac Mail stores everything for offline use these days so there are no settings to change. If you're using an older version of Mail, you may have to tell it to keep local copies of your email. 

POP vs. IMAP: a key difference.

If you use POP, you're used to being able to delete a message from your iPad, and have it remain on your Mac. With IMAP, if you delete a message from your iPad, it will disappear from your Mac. It may not happen immediately, but it will as soon as the account synchronizes. Many users have lost email when they first switch because they weren't briefed on this conceptual disparity.

To permanently retain email you receive via an IMAP account, copy it to a mailbox created using the "On My Mac" option. Note that if you move it, it's deleted from the IMAP account and won't be available on your other devices.

The Bird's the word

If you're looking for a faster method, you can employ Mozilla's highly capable Thunderbird email client as a liaison. You might even give the product a whirl while you're at it. This method is a bit tedious but it's considerably quicker with large amounts of email than waiting for it to upload and download via IMAP.

1. Create Finder a set of folders matching the folder hierarchy of your Outlook email in a suitable location. I use the desktop. They can all be top-level folders for this purpose, but it's less confusing to recreate the tree if you have lots of subfolders.

2. Open the folder you want to copy in Outlook, press Command-A to select all the messages, and drag them to the corresponding Finder folder you created. Each individual email will be created as an .eml file. Repeat the process for all your folders.

3. Download Thunderbird and install it in the applications folder.

4. Open Thunderbird and recreate your Outlook folder hierarchy.

5. Open your first Finder folder, press Command-A to select all the .eml files, then drag them to the corresponding folder in Thunderbird. Repeat until all the folders are transferred.

6. Open Mac Mail, select File>Import Mailboxes then select the Thunderbird option.

7. Mac Mail should already be pointing you at the correct location, but if not, it will be something along the lines of /users/"username"/Library/Thunderbird/Profiles/"random hash number"/Mail/Local Folders. You can find the full path in Thunderbird's Account settings dialog.

If you can't see the library folder...

a. Hold the option key while using Finder's Go function and you'll see Library as an option. Choose it, browse to the Thunderbird email folder, then copy it to a more accessible location.

b. Open a terminal and execute the command "chflags nohidden ~/Library/". This makes the Library folder visible even from a browser dialog. To reverse the process, execute the command "chflags hidden ~/Library/".

The IMAP method is somewhat slow, and the Thunderbird method can be tedious. But both are easy and don't require a payout for software that you might only use once in your life. That said, if you're in a hurry, or doing a lot of transfers, paid options from Stellar Phoenix and others are generally quick and easy.