Sometimes you may receive false notifications about your mailbox storage getting full.  If you want to check your actual mailbox storage, you can follow the steps below to verify:

 

  1. Login to Outlook web (office.com) and click Outlook link.  
  2. Then, click the gear icon in top-right.  
  3. Click “View all Outlook Settings”.
  4. Click “General”
  5. Click “Storage”