When a Windows NT 4.0 client compresses files on a server, it increases the CPU and memory usage on the server. If you wish to prevent Windows NT 4.0 clients from compressing files, remove the Everyone group from the ACL of %SystemRoot%\System32\Shcompui.dll, leaving Administrators and LocalSystem.
NOTE: DO NOT set Deny permissions as this will have unwanted consequences.
When the user attempts to compress a file, they will be greeted with:
Cannot load SHCOMPUI.DLL. Explorer cannot compress or uncompress at this time.
NOTE: When Service Pack 4 for Windows 2000 and Service Pack 2 for Windows XP are released, you will have a method for preventing compression on those operating systems.
NOTE: You can script this ACL change using Cacls.exe:
echo y| cacls %SystemRoot%\System32\Shcompui.dll /t /g Administrators:F System:F