How do I get Windows 10 Start Menu to tree all the folders?

Solution 1:

The toolbars in the Windows Taskbar still have the expanding folder (legacy Start Menu) functionality.

Add a toolbar to the Windows taskbar:

1. Right-click on a blank area of the taskbar.
2. Select Toolbars, New Toolbar...
3. Navigate to the folder of your choice, such as:
   • C:\ProgramData\Microsoft\Windows\Start Menu\Programs
4. Click "Select Folder"

Pro tip: You can still right-click on a menu item and click Sort by name.

Solution 2:

The Windows 10 Start menu is beautiful, but frustrating for someone who is used to Windows 7.

Your options as I see them are :

1. Use the free Classic Shell as replacement to the Windows 10 Start menu. Classic Shell has all the functionality of the Windows 7 Start menu (and even more).
2. Pin the folder to the Taskbar by pinning it first to the Start menu, then pinning that to the taskbar, then unpin from the Start menu.