- Create a folder on any local drive
	Example
	(c:\Dropbox) 
	- Hit the Windows or start button and choose Run:
 
	- Type: CMD to bring up a command prompt window
 
	- Load a command prompt and use the following :
	subst x: c:\Dropbox
	This will create what looks like a normal internal drive linking to that directory 
	- Open Dropbox and Choose advanced installation. Choose the folder you’ve created (x:\)
	Finish Dropbox installation 
	- Quit dropbox immediately after finishing installation
 
	- Return to command prompt and remove the virtual drive mapping with
	subst x: /d 
	- Map the drive to your network drive/NAS.
	Open any windows window
	Press Map Network Drive
	Assign the Mapped Drive to X
	Choose the Network Drive Location you’d like Dropbox to sync to 
	- Re-open Dropbox
 
 
출처 : https://wordpress.training-nyc.com/windows-7-training/dropbox-network-drive-windows-easy-training-tutorial/