How to Recover From a Broken Mail.app
After upgrading to Snow Leopard and starting up Mail.app for the first time I was notified that some of the plug-ins that I used under Leopard were not compatible and would no longer be active. No big deal, I figured until I looked at my Mail window.
One of the plug-ins I was using was WideMail. What WideMail does is turn your normally two rows of data in Mail.app (messages & preview pane) into two columns of data, arguably more suitable for wide-screen monitors.
The big trick here besides just physically moving the layout is that what WideMail does is create a new data column which contains the data of your choice (sender, subject, date received etc). You then disable the other columns and you are done, right? Wrong. Mail.app does not let you turn off the Subject column. WideMail hacks this and makes it disappear.
Fast forward. You install Snow Leopard, WideMail gets deactivated due to incompatibility and you go to turn on all your traditional Mail columns but Subject is still nowhere to be found. After trying to delete the WideMail packages, the plist files etc. the only solution I could find was to reinstall Mail. You can do this by
- Deleting the ~/Library/Mail folder (hopefully you are using IMAP so this shouldn't be much of an issue)
- Delete the file titled com.apple.mail.plist from the ~/Library/Preferences directory
- Inserting your install media
- Navigating to the Optional Installs folder
- Activating the installer
- Select Mail from the Applications section and reinstall
Following this you should be back up and running with a pristine version of Mail.app!