When managing emails in Outlook, the way your mailbox interacts with the server depends on whether you're using IMAP or POP3. With POP3, emails are downloaded to your device and often removed from the server, freeing up space. IMAP, however, synchronizes emails across devices while keeping them stored on the server, which may eventually lead to a larger or full mailbox.

If you want to keep all emails, the best long-term solution is to request that your administrator increase your email storage space. If upgrading storage is not an immediate option, here are some steps to free up space and keep your mailbox organized: