OS X Mail is great, until it breaks.

Sometimes doing something as simple as the "Rebuild" command will make all of your mail in a folder disappear.

Until the new version of Mail comes out in Leopard that resolves these issues, here's a way to get your mail back when it disappears like this.

When Mail "loses" your mail, in most cases it doesn't actually delete it, but it loses track of where it is. In fact, all of your messages are still sitting as individual files on your hard disk. Just go to your Home folder -> Library -> Mail -> and Mailboxes and you'll see folders of all your filed mail here.

Now, if you find a folder that has all of your missing emails in here, but that folder is still not coming up in Mail, try this.

First, make a copy of that folder, preferably on another disk or at least in another folder. That way, if someone gets royally messed up, you can always go back to the original.

Then, download this tool:

http://www.cosmicsoft.net/emlxconvert.html

Open up the utility in the download. Then drag the missing emails from your mail folder into the window of the application.

Hit the "Save mbox...'" button and save the resulting file on your Desktop and call it something like "Recovered Mailbox."

Now, go back to your OS X Mail, go to the File Menu and hit "Import Mailboxes..." and select the option for "Other." Then select the file that the utility above created and it will start to import.

Once it's done, look at the bottom of your OS X Mail folders for a folder called "Imported" and your mail will be there. Phew! Nothing should be lost.