Also, will there be any negative effects from using a different version of SFC_OS.dll than the rest of the files (say I integrate a newer SP2 build than what's currently available to the general public)? It seems to me that there's a potential liability there. Of course, when SP2 goes final, you could simply have RTM, SP1, and SP2 versions of the file and which one gets copied depends on which version of XP is detected.