If you’re not careful, emails can quickly pile up in your inbox, and this can prevent crucial emails from reaching your inbox if your company has placed tight restrictions on the amount of data your inbox can hold. Click the Size column in your inbox, and Outlook will sort your email according to those with the largest file size. Deleting one email with a 2MB attachment is equivalent to deleting hundreds of a smaller emails and can spare you from hand-picking emails to delete.