Mac folder which is Not Shared is shared and fully accessible from a Windows machine On my desktop, I right click on Macintosh HD and then on Get Info.
The Shared Folder checkbox is Unchecked and under Sharing and permissions, I have:


  system    (read and write)
  myUser    (me) (read only)
  wheel     (read &amp; write)
  everyone  (No Access)


However, if I access my Mac from a Windows machine, using the Mac's IP address, e.g \\192.168.2.1, I am initially asked to enter my credentials to gain access. I enter my Mac credentials. I then see Macintosh HD as a folder, and basically, the whole Mac system is visible. 

I can see the root folders, and access /Users/myUser and see all documents, pictures etc.

This is not good. 

If Macintosh HD is not marked as Shared, why do I see that as a shared folder? I believe that having myUser (me) listed under Sharing and Permissions might be the issue here. However, if I remove myUser, then I am not able to view root folders from the terminal/console. 

Thank you for all your input!
According to this answer on the Apple Support forum, if you enable (tick) a user for SMB sharing, it shares the root of the system drive (provided they are an Admin): 


  Users you have set up with accounts in Accounts preferences can access
  your computer by connecting to it over the network. A user with an
  administrator account can access your entire computer.


You can see the drive because you are an administrator, and you entered your password on the windows machine. If you hadn't entered your password (or had used a non-administrator account) you wouldn't have been able to see the drive.