Please check out Change the Font Size in Outlook's Folder Pane for the latest information on this topic.
A customer wants to know why they cannot change the font size in the Folder Pane (formerly Navigation Pane) in Outlook 2016. Here are the directions they used to follow to change it in Outlook 2010 but there isn't an Options Button there any longer:
Change the Navigation Pane font
You can change the font and size of the text in the Navigation Pane, from any view in Outlook.
On the View tab, in the Layout group, click Navigation Pane, click Options, and then click Font.
Enter the settings that you want in the Font, Font style, and Size boxes.
Click OK twice to close the open dialog boxes.
Is this no longer an option or has the location to make the changes been moved? I did research on Google as well as the Microsoft website and could not find anything for Outlook 2016.
My thanks, DoriLynn