Mail shows stale inbox count

Question

I've had some odd behavior on my OS X mail client. Heres' my inbox:

Yet here is how many unread messages I have:

These values used to be synchronized. Note that the first value will not change even if I mark all other messages as read (subfolders included).

OS X 10.7.4
Mail = Version 5.2 (1278)

Answer 1

Try these two solutions:

From the Finder hold down the <option> key and click on Go, this will show ~/Library/ in the list of items (it is hidden by default.)
Move the folder ~/Library/Mail/ to the desktop or another convenient location.
Launch Mail.app
From the File Menu choose Import Mailboxes...
Choose Import Data from Apple Mail
Navigate to ~/Desktop or wherever you moved ~/Library/Mail/ to
Click on Choose
Wait until it imports

Or

In a Finder window, navigate to Username/Library/Mail/V2/MailData, and delete any file that begins with Envelope Index, such as "Envelope Index" or "Envelope Index-shm" or "Envelope Index – wal". In my case, I had all 3 of these Envelope indexes, and moved them to the trash. NOTE: When accessing Library, keep in mind that your home Library is hidden in Lion. To access it, from the Finder, hold down the Option key and click on the Go menu. The Library should be then be shown in the menu and you can select it.

Restart Mail. It will then rebuild a new list of messages, which can take some time, so be patient. Another NOTE for EXCHANGE users: After removing the Envelope Indexes, my Exchange account email content was blank. To revive it, I had to delete my Exchange email account and add it again fresh. After adding it from scratch (and the download took a while since I have about 12K messages), the mystery Unread Message notifications were gone.