Q: Can we disable the default Windows administrative shares (C$, D$, Admin$, IPC$) to lock down some of our Windows servers?

A: You can remove the administrative shares on a Windows box and prevent them from being created automatically by editing the following registry key and setting its value to 0: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters\AutoShareServer. To apply this change, you must stop and restart the server service, which you can easily do by entering the following commands at the command prompt:

net stop server
net start server

However, Microsoft recommends that you don't remove administrative shares because it can break many different things. For a list of problems that can occur, have a look at the Microsoft article "Overview of problems that may occur when administrative shares are missing."