Apple Mac OS X hints and tips and tweaks
Fix faults with Mail
Mail on the Apple Mac is by far the most popular email client and it is a great program. Not because it is packed with features, but because its functionality can easily be extended by means of plug-ins. There are lots of them and they add a wide range of features and functions that aren't available in the bare bones program. However, sometimes two plug-ins can clash and they won't work together. They might even stop Mail from starting completely. Some plug-ins are quite old and they were originally designed for the previous version of OS X and this can cause problems too.
Snow Leopard is sufficiently different to Leopard that plug-ins won't work unless they are modified. Consequently you may have incompatible plug-ins on your Mac or you might download and install plug-ins for Leopard that prevent Snow Leopard's Mail from working properly. Fixing problems with plug-ins and repairing other Mail faults is easier than you might expect. Here's how to do it.
Open a Finder window and go to your home/Library/Mail folder. Look for any files that belong to plug-ins. The plug-ins themselves aren't here, but sometimes they create files here for data storage, configuration settings, and so on. Look for filenames that are variations of the plug-in name.
After removing any obvious plug-in data files, open the Bundles folder. This is where the plug-ins are stored. Delete the problem plug-in if you know which one is causing the difficulties or simply delete them all if you want to remove every plug-in from Mail.
Go to the root of the hard disk drive and then to /Library/Mail and repeat the process. Look for data files named after the plug-in and then open the Bundles folder and remove the problem plug-in or clear the lot out as you prefer. Plug-ins that are installed for all users are in the /Library/Mail/Bundles folder, but plug-ins that are installed just for you are stored in home/Library/Mail/Bundles.
Go to the home/Library/Preferences/ folder and look for any file that contains the plug-in name because plug-ins store information in plist files here. Also look in /Library/Preferences too.
That's it. You should restart the Mac and the problem plug-ins (or all plug-ins) have been removed. Mail should be OK now.
Rebuild the indexes
If the problem is with corrupt email messages, missing messages, missing inboxes, faulty inboxes, and so on, the best thing to do is to rebuild the indexes used by Mail. Select Mailbox, Rebuild. Quit Mail afterwards and restart it. Clearing out the plug-ins and rebuilding the indexes should cure most problems with Mail and hopefully it will now be working properly.