OIT Home > OIT Knowledge Base Search Knowledge Base: How do I open a Resource Mailbox room or equipment in Outlook 2013/2016? To open a Resource Mailbox Room in Outlook 2013/2016, please follow the instructions below. In order to see newly added Users or Rooms, you may need to manually update the Global Address List (GAL). From the Calendar pane, on the Home tab, select Open Calendar > From Room List under the Manage Calendars Group. Room: Under Address Book choose All Rooms. (This will list all available Resource Mailbox Rooms.)Equipment: Under Address Book choose All Equipment. (This will list all available Resource Mailbox Equipment.) You can then either double click on the Room/Equipment you want to choose and it will appear in the Rooms/Equipment field at the bottom of the screen, or you can highlight the Room/Equipment and then select the Room button to add it to the Room field. Select OK. The Resource Mailbox Room/Equipment you have chosen will appear under Rooms in your Calendar lists. Need more help?