Forwarding Messages in Mail Using Rules

If you’re using Mail’s rules to forward a message and can’t figure out why the message isn’t being sent, check the number of addresses you’re forwarding to. On OS X 10.7.4, at least, it seems that Mail doesn’t like more than one address and will generate an error to that effect in Console:

8/20/2012 2:01:57.336 PM Mail: exception raised in routeMessages: -[IMAPMessageWithCache libraryID]: unrecognized selector sent to instance 0x7fb423801ca0

Use a separate rule for each address.