Keep the Folder List view in the Navigation Pane
In Folder List view, all your folders, including your Inbox folders, will remain visible in the Navigation Pane when you switch to other views, such as Calendar or Contacts.
To see the Folder List view, click Folder List at the bottom of the Navigation Pane.
Keep the Folder List as your main view
If you switch to the Folder List view and then close Outlook, you will see the Folder List when you open Outlook again. However, if you navigate away from the Folder List view by using one of the Navigation Pane buttons (rather than clicking a folder in the Folder List), the Navigation Pane view will revert to the default view of the buttons with smaller panes related only to that view.
For example, if you click the Calendar button, the Calendar view will be displayed in your main Outlook window, not the Folder List view. Using the Calendar button resets the Navigation Pane to a view that applies only to the Calendar.
Hide the large buttons and increase the space in the Navigation Pane
To avoid clicking the large buttons at the bottom of the Navigation Pane and to gain more space, you can change from large buttons that are displayed vertically at the bottom of the pane to small buttons that are displayed horizontally across the bottom of the pane. Point to the horizontal splitter bar between the folders and the buttons. When the pointer turns into a double-headed arrow , drag the splitter bar up or down.
If you drag the horizontal splitter bar to the bottom of the Navigation Pane, all the large buttons will be converted to small buttons and will appear in a single row at the bottom of the pane.
Hide the Folder List and go back to the Mail pane view
At the bottom of the Navigation Pane, click the Mail button or Mail .