Apple is working on a fix to address issues with the native Mail client in OS X Mavericks, including problems with Gmail, stability, and smart mailboxes, reports 9to5Mac.
There have been widespread reports of Mavericks users experiencing problems receiving messages, sorting messages into folders, and deleting messages. Apple is aware of the problem and has seeded an updated Mail app to both Apple employees and testers in Apple's AppleSeed customer program.
Currently, the update is only available as a downloadable patch for Apple employees and testers rather than a regular update to Mavericks. While OS X 10.9.1 is well into development, it's not yet known whether the Mail update will roll out separately or be included with OS X 10.9.1.- Use Mail with your usual Mail accounts, including iCloud, Gmail, Exchange, etc.
- Send Mail messages
- Receive and check for new Mail messages at the intervals you expect it
- Read and move Mail messages to folders on your mail server, folders on your Mac, smart folders.
- Delete Mail messages as appropriate
- Undo move or delete actions with your Mail messages
- Mark messages read/unread in both your mail provider's webpage and Mail and verify they stay in sync.
Article Link: Apple Working on Fix for OS X Mavericks Mail App Issues