Replacing protected library files in use is a chore. Yesterday, I had to replace some PGP 8.0 DLLs with debug versions so I could step through PGP code. Since they are in use, I tried to use a Microsoft command-line tool inuse.exe to schedule those DLLs to be replaced after reboot. Unfortunately, the files were protected by WFP (Windows File Protection). So I disabled WFP temporarily by changing a registry setting. Still a no go. Frustrated, I tried something that shouldn't have worked. I renamed the DLLs and copied over the replacement DLLs. Now I am stepping through PGP to chase down a bug. Windows security is unreal.