When you use SetupMGR to make your answer file. It also creates a bat file. Like displayed. rem This is a SAMPLE batch script generated by Setup Manager. rem If this script is moved from the location where it was generated, it may have to be modified. rem set AnswerFile=.\unattend.txt set SetupFiles=E:\i386 E:\i386\winnt32 /s:%SetupFiles% /unattend:%AnswerFile% So, your command would be E:\i386\winnt32 /s:E:\i386 /unattended:.\unattended.txt Assuming that E: is the setup drive. Or you can use a cd boot method and rename unattended.txt to winnt.sif, and put it in i386 directory.