I don't know what happening when you run your command. Do you get any error message? To find out which step(s) in installation process fail I would try to run this MSI in 3 steps: 1. msiexec.exe /i "%WPIPATH%\Install\NOD32_3.0.621\eavbe_nt32_enu_30621.msi" (without any switches) if it works, go to step 2. 2. msiexec.exe /i "%WPIPATH%\Install\NOD32_3.0.621\eavbe_nt32_enu_30621.msi" /qn. if it works too, go to step 3. 3. msiexec.exe /i "%WPIPATH%\Install\NOD32_3.0.621\eavbe_nt32_enu_30621.msi" /qn /cfg=%WPIPATH%\Install\NOD32_3.0.621\gbmNOD32v3settings.xml If it still doesn't work, put </l* c:\eavbe.log> in the end of your command to find out what's happening when Msiexec.exe trying to install that MSI-file.