How to check my O365 mailbox usage?

You can check your O365 mailbox quota and usage in the "Options" of Office 365 Outlook Web App (OWA):

  1. Login your O365 account at CityU Staff Sign in to Office 365 web page.
  2. Click gear icon at the top-right corner of OWA window.
  3. Select Mail under Your app settings.

  4. Select My account under General. The Mailbox usage of your mailbox will be shown.

    Mailbox Usage


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