How To Locating Missing Mac Mail
In the network, the electronic mail box can automatically receive the network any electronic mail, and can store the specified size and other electronic documents.
Q. I seem to be missing some messages in the OS X 10.11 Mail app that I know I didn’t delete, and they show up when I look for them with the main Mac search box. Where are these messages, and is there a way to get them back in the inbox?
A. First of all, check to make sure your mailbox has not inadvertently re-sorted the messages into a different order from what you normally see. Accidentally clicking on the label at the top of an inbox column will reorder the messages accordingly by sender, subject or other category, so if you are used to seeing mail as it comes in, click the top of the Date Received column and make sure it is set to show the messages in the chronological order they arrived.
If the messages are still missing, it is likely that the internal database that the Mail program uses to index your messages is out of whack. You can rebuild this index, though, which will probably correct the problem and any issues related to a misbehaving mailbox. Other symptoms include the inability to delete messages, incorrect notifications of unread messages in the mailbox, garbled messages, slow performance of the Mail app and mailboxes that appear to be empty when you know they are not.
To rebuild the index of messages, select the mailbox you want to fix from the list on the left side of the Mail window, then go to the Mailbox menu and choose Rebuild. (If you do not see the list of mailboxes on the side of the Mail window, go to the View menu and select Show Mailbox List.)
It may take a few minutes for the Mail program to rebuild the selected mailbox, especially if the account uses the IMAP or Exchange systems. During the rebuilding process, these mailboxes will appear disconcertingly empty for a short time because the messages (and their attachments) are removed from the Mac before the Mail app downloads them all over again from the original mail server. Once the rebuilding is complete, everything in the mailbox should be back in place again — including the messages that were originally missing.