Outlook - Opening Shared Mailboxes/Folders In Outlook Here is how to open the shared mailbox/folders in Outlook.(Note: Microsoft hides this setting well, so please let me know if you'd rather have me remote into your computer and set this up.)1) Click File > Account Settings > Account Settings...2) Click Change...3) Click More Settings4) Click the Advanced tab > Add...5) Type in the username of the folder sharer and click OK6) Click OK7) Click Next8) Click Done/OK to close any remaining popup Windows that we opened previously.9) Back in the main email window, scroll to the bottom of your folders. You should see the shared mailbox here. Click the arrow beside the mailbox to expand the folder and subsequent folders.