When you open File Explorer on Windows 10 Technical Preview, it opens to Quick Access by default. Think of Quick Access as a section where you can place shortcuts to your favorite folders. It also displays recently viewed files and frequently used folders by default. We’ll show you how to use Quick Access and what checkboxes to uncheck if you’re concerned about other people seeing your most frequently viewed folder.
More details: http://www.windowscentral.com/how-to-quick-access-windows-10-technical-preview