yes !!!!! you have the answer of my problem: the installshield try to make a setup.log on the cd,so it can't!! like you say,we have to use the f2 switch... this is my command %cdrom%\app\software.exe -s -f1"%cdrom%\app\software.iss" -f2"%systemdrive%\install.log" and after: DEL "%systemdrive%\Install.log"