PowerShell Start-Process infinite execution of installer

Question

I have Inno Setup installer that run in very silent mode (it's working).

But when I'm running my Inno Setup installer through PowerShell script with admin rights – I get endless execution. Also, the following script code (SetEnvironmentVariable) is not executed even after successful installation.

$installerArguments = $requiredInstallerArguments + $additionalInstallerArguments

Start-Process -FilePath $installerFile.FullName -ArgumentList $installerArguments -Wait

[Environment]::SetEnvironmentVariable('WebPort', (GetValueByKey -array $additionalInstallerArguments -key "/webport"), [EnvironmentVariableTarget]::Machine)

Why does this happen and how to fix it?

Answer 1

Sometimes I have to use the .WaitForExit() method

$Process = Start-Process -FilePath $installerFile.FullName -ArgumentList $installerArguments -PassThru
$Process.WaitForExit()

Start-Process ... -Wait behaves differently than (Start-Process ... -PassThru).WaitForExit() / Start-Process ... -PassThru | Wait-Process: the former waits for the entire child process tree to terminate, whereas the latter return once the immediate child process has terminated (see GitHub issue #15555). Thus, if an installer spawns a child process that keeps running after the installer has exited, -Wait won't return until that child process terminates.

In SysInternals Process Monitor, you can use Tools->Process Tree to see these process trees.