Analysing the file content of Windows Installer files using PowerShell

A few weeks ago we have started with the preparation for introducing Microsoft Office 2013 and Internet Explorer 11. As with every introduction of new software it’s all about compatibility. During the course of testing applications we were informed that some of them caused an issue due to hard coded paths. Each application is going to be installed anyway so that application owners can conduct testing, but at the same time I thought, it would be nice if we could identify potentially affected applications upfront without having to go through an actual install.

Here’s an example of an application that has a hard coded path to Microsoft Office 2010. The Directory is defined as Office14 which translates to the Office 2010 Installation directory.

As most of you probably know, a Windows Installer file is a database that contains all the necessary information for the installation of an application. In order to query the files referenced within the Windows Installer database, we have to look at the following database tables.

Let’s start with the File Table. In the below example we see that this Application consists of two files. The File Table contains the following attributes: File, Component_, FileName, FileSize, Version, Language, Attributes and Sequence.


To find out in which directory this file installs, we first have to look at the Component table which has the following attributes: Component, ComponentId, Directory_, Attributes, Condition and KeyPath.


To link these two tables, we use the FileName attribute of the file table and Component attribute of the Component table. So far we know that the file iPublish_.dotm.lnk is going to be stored into the STARTUP folder. Now we only need to find out where the STARTUP folder is going to be, so we are going to look at the Directory table.


And there it is, the STARTUP directory. But we still don’t know where the file is going to be stored, as we first need to resolve the other Directory entries. If you study the directory table for a while, you notice that there is some logic in here.


To link the Directory table with the File and Component data, we join the Component table Directory_ attribute with the Directory table Directory attribute. However this still doesn’t give us the information where the file is going to be stored on the system, unless we would try to resolve the various entries within the Directory table, that to be honest would end up in a complex script (at least for me).

But then I found this forum post on stackoverflow discussing how to resolve MSI paths programmatically by calling the CostInitialize and CostFinalize Actions. The result of calling these actions is that the full file paths are resolved.

So now that we know what pieces need to be tied together, let’s turn this into a PowerShell script. I had a few challenges here. When calling the Windows installer object to invoke the CostInitialize and CostFinalize actions directly from within the PowerShell script that contains the Get-MSIFileInfo function, the Windows installer session would not close. So had to launch this in a separate process and then process the results within the calling script. This is why you find a complete PowerShell script defined in the $launchmsiscript variable.

When running the function against one or multiple Windows installer databases, the results are exported into a text file containing the following attributes for each file.



The entire script can be downloaded from here


One Reply to “Analysing the file content of Windows Installer files using PowerShell”

  1. Thanks for this, I have a load of vbscripts for messing with MSIs but nothing in PowerShell yet! Something you might want to add, packages made by Visual Studio and some other tools set the main install dir via a custom action, so you may want to add support for that too.

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