I’ve created a Wix installer that installs some of our software and copies two .msi files (3rd party products) into the install folder.

In a Custom Action we call our own software with a /register command line parameter, which does what needs to be done to register our own software and then tries to us msiexec to install the other two msis

Our own software registers correctly but the two msi files fail.

This is how we defined our Custom action:

    <InstallExecuteSequence>
        <Custom Action="InstallProtocol" After="InstallFinalize">
        </Custom>
    </InstallExecuteSequence>

Registering our own software works correctly.

After this, though, our software needs to call msiexec /i to install the additional pieces of 3rd party software from their respective .msi files

When I don’t add the Custom Action, I just install our software, run a CMD and run oursoftware.exe /register it proceeds quite happily to the two msiexec /i statements and it installs the 3rd party software.

But it doesn’t do it from the Custom Action. I am thinking that this is probably because the msiexec statement we use to install our own software is still running and Windows runs into the problem where it says “Another Installation In Progress Please Complete Installation Before Continuing” and it doesn’t perform the two msiexec /i commands for the 3rd party software

My question: is there a way I can modify the Custom Action so that, yes, it launches our software as intended, but it then completes its own msiexec call?