Mail uses several indexes known as the Envelope Index to search message headers, so such problems can normally be resolved by forcing Mail to completely rebuild the Envelope index, as follows: the message body), because Mail uses two different systems to search each item. It depends whether you’re having problems with headers (such as the To, From, Subject, and CC fields) or the message content (i.e. There are a few more solutions to fix possible Mail issues. In most cases, this is likely to fix any issues that you may be encountering. The selected mailbox will be rebuilt and messages from the server re-downloaded. In Mail, select the desired Mailbox from the left-hand panel.To rebuild a mailbox, proceed as follows. Therefore, it’s wise to try the other methods first if your mailbox is particularly large. This solution can take quite some time because all messages will be deleted from your Mac. Mail can completely rebuild your mailbox, which can fix many of the most common problems with missing email.
