I'll deal with the ASCII version of this struct. The OSVERSIONINFOEX according to MSDN has some of the formerly reserved data at the end of the struct filled in. In particular, wSuiteMask and wProductType now exist where some of the wReserved data once was. The only problem is, my winbase.h file has the old version. I believe my SDK is updated. What's the story with this struct? Is it supposed to be updated or what?