If you use an Exchange account, you can choose to store draft, sent, junk, and deleted messages on the server, and when to erase junk and deleted messages. The blue color shows up prominently in your Outlook 2013/2016 inbox when new email messages come in, with a bold blue subject line and a blue bar indicating an unread message. Select a mailbox on the mail server to store archived messages. Love it or hate it, you see a lot of it when you use various Office products, especially Outlook 20. If your email account provider sets up the server to delete older messages, the messages are deleted regardless of how you change this option. If you selected None for Trash Mailbox, you can have Mail permanently delete messages automatically. Select a setting other than Never to avoid exceeding storage limits set by your email account provider. Mail erases deleted messages at the specified time. This option is available only for IMAP accounts. Select a mailbox on the mail server or on your Mac to store deleted messages, or choose None (deleted messages are removed and aren’t available in the Trash mailbox). Mail automatically deletes junk messages at the specified time. Note: Select this option on each Mac where you’ll use your account, to avoid having two Junk mailboxes in the Mail sidebar.
