I recently discovered to my chagrin that Apple Mail on my MacBook Air would no longer start. This was part of a much larger set of problems that this machine was starting to demonstrate including slowdowns, application lockups and other issues.

In doing some research on how to fix this problem, I discovered a series of threads I wanted to share with you. Many Mail issues can be resolved through rebuilding the index for Mail. Here’s how.

1. Open ~/Library/Mail where the ~ represents your user home folder
2. Drag the file called Envelope Index to your desktop
3. Make sure this file no longer shows in the Mail folder
4. Relaunch Mail
5. Accept the prompt to import messages
6. Review any messages telling you that your machine is out of sync with MobileMe and make the decision that best suits your data.
7. You’re done

If this doesn’t work for you completely, you’ve got a bigger problem, but it does solve a number of issues.