OK. Verify/repair the startup disk (not just permissions), as described here:
The Repair functions of Disk Utility: what's it all about?
After having fixed
all filesystem issues, if any, and making sure that there’s enough space available on the startup disk (a few GB, plus the space needed to make a backup copy of the Mail folder), try this:
1. If you have a .Mac account and .Mac synchronization of Mail data is enabled either in
Mail > Preferences > General or in
System Preferences > .Mac, disable it before proceeding.
2. Quit Mail if it’s running.
3. Make a backup copy of the
~/Library/Mail folder, just in case something goes wrong while trying to solve the problem. You can do this in the Finder by dragging the folder to the Desktop while holding the
Option (Alt) key down, for example. This is where all your mail is locally stored.
4. In the Finder, go to
~/Library/Preferences/. Locate
com.apple.mail.plist and move it to the Desktop (to be deleted if this fixes the problem).
5. Open Mail. You’ll have to set up your non-.Mac accounts from scratch all over again. If given the option to import existing mailboxes or something like that,
don’t. Just enter the account information and Mail will automagically rediscover the data in
~/Library/Mail/ when done.
6. You’ll have to re-configure most of your settings in
Mail > Preferences. For spam-related security reasons, the first thing you should do is go to
Preferences > Viewing and disable
Display remote images in HTML messages if it’s enabled.
7. You may also need to re-install or re-enable any Mail plug-ins you have installed for Mail to recognize them.
8. As a side effect of re-creating
com.apple.mail.plist, Mail might rename
Outbox (which is where messages waiting to be sent are stored) to
Delivered. The name of that mailbox is actually a misnomer, as it would contain messages (if any) that couldn’t be delivered for some reason. You can delete that mailbox if you wish.
9. If the problem is fixed now and .Mac synchronization of Mail data was enabled at the beginning, enable it again, go to
System Preferences > .Mac > Advanced, click
Reset Sync Data, and choose the appropriate options to reset the Mail data stored on the .Mac server with the data locally stored on the computer, i.e. sync data must flow from the computer to the .Mac server.
Note: For those not familiarized with the ~/ notation, it refers to the user’s home folder. You can easily locate any of the folders referred to in this post by copying the folder path here, doing Go > Go to Folder in the Finder, and pasting the folder path there.
