Empty mailbox in Yahoo Mail
Are your emails and contacts missing? If you haven't signed in to Yahoo Mail for 12 months or more, your mailbox is considered inactive. An inactive mailbox stops receiving new emails, and all mailbox contents, folders, contacts and settings are permanently deleted.
Keep your mailbox active
Yahoo Mail maintains the content of your mailbox as long as it remains active. Sign in to your mailbox at least once every 12 months to keep it active. Content deleted from an inactive mailbox can't be restored.
Reclaim an inactive mailbox
An inactive mailbox can be recovered by signing in to it. This action only reclaims the email address, not the original contents of the mailbox. Custom mailbox settings created before an account became inactive need to be created again.