R – Launch program after msi installation

EDIT: Perhaps look at the answer currently immediately below.

This topic has been a headache for long time. I finally figured it out. There are some solutions online, but none of them really works. And of course there is no documentation. So in the chart below there are several properties that are suggested to use and the values they have for various installation scenarios:

So in my case I wanted a CA that will run only on uninstalls - not upgrades, not repairs or modifies. According to the table above I had to use

<Custom Action='CA_ID' Before='other_CA_ID'>
        (NOT UPGRADINGPRODUCTCODE) AND (REMOVE="ALL")</Custom>

And it worked!

The easiest way I have found to detect a 64-bit operating system is to use the VersionNT64 property. This property can be used in conditions for components or custom actions (eg. the condition Not VersionNT64 will only be true for 32-bit operating systems).

As for installing other MSI packages during your installation, that is a little trickier. Windows Installer will only allow one MSI to be running the Execute Sequence at a time. This means that you must either install your Crystal Reports MSI during the UI Sequence using a custom action (be careful if you do this, the UI Sequence is skipped if the MSI is run in silent mode), or create some kind of bootstrapper program that will run both the Crystal Reports MSI and your own in sequence.

I have never created my own bootstrapper, but InstallShield has a bootstrapper program built into their setup.exe; they call packages installed this way prerequisites.