changing back the settings. The policy file is usually distributed through a LAN, but can be placed on the local computer. The policy file is created by a free tool by Microsoft that goes by the filename poledit.exe for Windows 95/Windows 98 and with a computer management module for Windows NT. The editor requires administrative permissions to be run on systems that uses permissions. The editor can also directly change the current registry settings of the local computer and if the remote registry service is installed and started on another computer it can also change the registry on that computer. The policy editor loads the settings it can change from .ADM files, of which one is included, that contains the settings the Windows shell provides. The .ADM file is plain text and supports easy localisation by allowing all the strings to be stored in one place. Virtualization INI file virtualization Windows NT kernels support redirection of INI file-related APIs into a virtual file in a registry location such as HKEY_CURRENT_USER using a feature called "InifileMapping". This functionality was introduced to allow legacy applications written for 16-bit versions of Windows to be able to run under Windows NT platforms on which the System folder is no longer considered an appropriate location for user-specific data or configuration. Non-compliant 32-bit applications can also be redirected in this manner, even though the feature was originally intended for 16-bit applications. Registry virtualization Windows Vista introduced limited registry virtualization, whereby poorly written applications that do not respect the principle of least privilege and instead try to write user data to a read-only system location (such as the HKEY_LOCAL_MACHINE hive), are silently redirected to a more appropriate location, without changing the application itself. Similarly, application virtualization redirects all of an application's invalid registry operations to a location such as a file. Used together with file virtualization, this allows applications to run on a machine without being installed on it. Low integrity processes may also use registry virtualization. For example, Internet Explorer 7 or 8 running in "Protected Mode" on Windows Vista and above will automatically redirect registry writes by ActiveX controls to a sandboxed location in order to frustrate some classes of security exploits. The Application Compatibility Toolkit provides shims that can transparently redirect HKEY_LOCAL_MACHINE or HKEY_CLASSES_ROOT Registry operations to HKEY_CURRENT_USER to address "LUA" bugs that cause applications not to work for users with insufficient rights. Disadvantages