JSI Tip 6447. How do I prevent Windows NT 4.0 users from compressing files?

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

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