Thanks, but I guess I should explain more. I was able to get makecat.exe and mscat32.dll. What I am looking for is documentation on the details. What do I need to do to create the catalog files. I imagine from reading the files inside of a catalog that there is much to be learned to create the .inf and others files, to convert a .CAB or a KB executable to a .CAT. Unless I am completely misunderstanding the process and the makecat.exe does it all for you. I have a Unix/Linux background so I'm not afraid to read docs or create and edit text files. I'm just having trouble finding out where to start.