A mailbox at quota may stop receiving new messages. Before deleting mail, identify what must be retained and whether another device holds a reliable copy.
Review and clean deliberately
- Open Email Disk Usage and choose the affected account.
- Compare folder sizes and message counts. Sent, Trash and Spam can be as significant as Inbox.
- Review the available cleanup criteria and preview the scope wherever possible.
- Export or archive required records through a supported workflow before removing them.
- Confirm the selected mailbox and folder before deletion, then recheck quota and test incoming mail.
Synchronisation matters
Deleting mail in an IMAP mailbox can remove it from synchronised devices too. A downloaded mail client is not automatically a backup if it mirrors server deletions. Follow your business retention rules rather than deleting everything older than an arbitrary date.
If storage keeps growing, review attachment practices, automated notifications and forwarding arrangements. Increase a quota only within the account’s total allocation. An unlimited mailbox setting cannot create physical storage that the hosting account does not have.
Use a monitored archive and a documented retention policy for records you must keep. Ask support before manually changing mailbox files in File Manager.
Official references
Reviewed 2026-10-22. Menus and availability depend on your hosting plan and server configuration.