Cacls.exe May Not Redirect Output to a File

When you use the Windows NT Cacls.exe command to redirect access control list information to a file instead of the screen, you may get unexpected results depending on the version of Cacls.exe that you are using.

Cacls.exe is a command-line utility that ships with all versions of Windows NT. It can display, replace, or edit, existing Access Control Lists (ACL) for files and directories on an NTFS volume. Cacls.exe is useful for resource administration and can also be helpful for troubleshooting issues related to permissions.

You can use Cacls.exe with the /t and /c switches to display ACL information.

For example, if you have a directory called c:\temp and you wanted to display the ACL for this directory, subdirectories, and its files, you could issue these commands: You can also output the result to a text file with this command: The expected behavior is that the information would be written to a file rather than to the screen. However, under Windows NT 4.0 Service Pack 2, the file is created, but contains only blank lines. Redirecting using the pipe (|) symbol opens Notepad with the appropriate filename, but again the file itself is empty.

To resolve this problem, use the original version of Cacls.exe from Windows NT 4.0.

Microsoft has confirmed this to be a problem in Windows NT version 4.0 Service Pack 2.