Mac下Mail未读邮件数的修正

https://discussions.apple.com/thread/3780528?tstart=0

Quit Mail if it’s open.
In ~/Library/Mail/V2/MailData, delete any file that begins with “Envelope Index,” such as Envelope Index or Envelope Index-shm.
Your home Library folder is hidden by default. To display it, choose Finder > “Go to Folder” and then enter “~/Library.”
Open Mail.
Mail creates new Envelope Index files. This process may take a few minutes, depending on how many messages Mail is reindexing.