Er, im not real sure if you are right about this (I havent checked but it doesnt square with my feeble and fallable memory.) But if you are then I would try to get a lock on the file. Afaik, Win32 will lock the file while copying so if you can get an exclusive lock on the file it must be done. IME, mtime is safe to use, ill have to look into this deeper and see where the discrepancy comes from.