How to Exclude OS X Mail Messages from Time Machine Backups

Cloud connected to cables in sky
Blend Images/Jon Feingersh / Getty Images

First, on the server's disks; then, as numerous backups covering weeks at least at that and another location was chosen by the email provider; in some three email programs all insisting on local copies (on the same disk admittedly) for search and speed; finally, in Time Machine backups.

How many copies do a good backup make?

If you think you can forego one of the copies, how about OS X Mail's Time Machine backup?

While there's no keeping Mail from storing messages in an IMAP account locally, preventing Time Machine from backing up these messages is easy.

Time Machine backups will be faster, and the reduced amount of data lets Time Machine keep backups for other—crucial—data for longer.

For messages kept only in OS X Mail (say, those in a POP account you download), Time Machine backups are still eminently useful, of course. If you have accounts of both types, you can easily have only one included in backups; you can choose by account—and email folder even.

Exclude OS X Mail Messages from Time Machine Backups

To stop Time Machine from backing up messages in your OS X Mail folders (especially for IMAP accounts that are already backed up both at the server and in Mail itself):

  • Select System Preferences… from the apple menu.
  • Open the Time Machine category.
  • Click Options….
  • Click + beneath Exclude these items from backups:.
  • Press Command-Shift-G.
  • Type "~/Library/Mail/V2/" (not including the quotation marks) under Go to the folder:.
  • Click Go.
  • Highlight the folders corresponding to the email accounts you want to exclude from Time Machine backups.
    • Folders will usually include the username and server used to log on as well as "IMAP-" at their beginning.
    • Highlight the Mailboxes folder for local OS X Mail folders (including Outbox).
    • Hold down Command to highlight multiple folders and Shift to highlight a range. You can also draw a rectangle with the mouse cursor to select a group of folders.
  • Click Exclude.