This has occurred several times already ( I guess few months apart ). My Apple Mail suddenly decided to download several thousand messages. Today, it is 4957 messages, to be precise. Of course, I do not have so many new messages. The mailbox shows only 2 new messages at this point, and those are probably correctly labeled as new. There do not seem to be duplicate messages in Mail after this finishes. I do not know if there is some duplicate storage for the emails/attachments that are re-downloaded. I am using IMAP access to Gmail. Even if there is no harm in Mail doing this, it bothers me.... Looking for any info/comments/suggestions on this. Thanks, PaulCC.