Per the vendor (formerly SPSS, then IBM, now HelpSystems) the ShowCase Client Update 9 FP3 installer does not support silent/unattended installs. Although you can pass the "/S /v/qn" command switches to the installer, it will not correctly update the installation and will in some cases break your ShowCase 9.0 installation.

... Or, you can extract the Installscript msi from the executable, then using an MSI editor make the following modifications to the MSI, either directly or via a transform:

Add the property ISSETUPDRIVEN to the property table and give it a value of 1.

Add a condition to the "OnCheckSilentInstall" custom action in the InstallExecuteSequence that always resolves to False or remove the custom action from the sequence.

Make any additional changes required, such as populating the serial number, modifying shortcuts or feature states.

Note that the method described above does not solve 100 percent of all cases. In some cases, the MSI file contains no internal dialogs, and instead the setup.exe file handles user dialogs by interacting with custom actions in the MSI. These custom actions will fail if setup.exe is not running. There is no simple solution to this.

However, there are known custom actions to remove from MSI files exhibiting this behavior. Removing these custom actions will give you a much greater chance of successfully freeing the MSI from its dependency on setup.exe

The custom actions are:

ISVerifyScriptingRuntime

ISStartup

OnCheckSilentInstall

OnGeneratingMSIScript

OnMoving

OnFeaturesInstalling

OnInstallFilesActionBefore

OnInstallFilesActionAfter

OnFeaturesInstalled

OnMoved

OnGeneratedMSIScript

ISRebootPatchHandler

Exercise caution in removing more than the listed actions as you could inadvertently remove a custom action that is required to install or configure parts of the application.

In order to run the msi, you'll have to install an appropriate version of the InstallScript engine on your target machine first. Seems to have worked pretty good so far.