This policy setting determines whether case insensitivity is enforced for all subsystems. The Microsoft Win32? subsystem is case insensitive. However, the kernel supports case sensitivity for other subsystems, such as the Portable Operating System Interface for UNIX (POSIX). Because Windows is case insensitive (but the POSIX subsystem will support case sensitivity), failure to enforce this policy setting makes it possible for a user of the POSIX subsystem to create a file with the same name as another file by using mixed case to label it. Such a situation can block access to these files by another user who uses typical Win32 tools, because only one of the files will be available. Fix: (1) GPO: Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options!System objects: Require case insensitivity for non-Windows subsystems (2) REG: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Kernel!ObCaseInsensitive