In 10.5.2, Mail tends to often not show a count for unread emails in folders and sub-folders, especially after a reboot or relaunch caused by a system freeze or crash.The workaround is very easy: create a new Smart Folder with the only rule being Message is unread. This folder will contain all unread messages from all folders, and also show the name of the messages' parent folder in the Mailbox column. For whatever reason, the Smart Folder count will remain visible and accurate, even after a relaunch of Mail.[robg adds: I can confirm this problem exists, as just this morning I had to force quit Mail. I had a dozen or so unread messages in various mailing list folders, but none showed as having unread messages after a relaunch. My Smart Folder, though, had an accurate count icon, so I was saved having to dig through the various folders to find the new messa...

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