Cannot open Mail Preferences in Mountain Lion I have a user that whenever she tries to open mail preferences it consistently locks up with the pinwheel icon and requires her to force quit mail. Mac mail was fine until a gmail account was added to her list of accounts. 

Aside from the prefs issue, Mac mail runs fine. She has 10.8.2 installed. When she called Apple, they suggested reinstalling the OS by using the recover option at bootup. 

Is there a trick we can do at the terminal, finder or elsewhere to fix mail? The same issue exists in safe boot.

Does mail have a way to easily reset preferences while retaining the accounts configured and rules.
Go to ~/Library/Containers/com.apple.mail/Data/Library/Preferences and move the file com.apple.mail.plist to the Desktop and restart Mail.

Other plist files exist in ~/Library/Mail/V2/MailData/ but I'd start with the above plist first. In this directory you could also manually remove the offending account (particularly if the mail is also stored online) and re-add it.