The Windows 8 Metro App delivery and installation mechanism has a lot of new plumbing!  When you experience a problem, it is a big challenge to figure out everywhere you might look to solve the problem.  I am a big proponent of gathering existing logging data whenever I start to work on a problem - mainly because the data is there for zero effort!  Sure I can slap on procmon and dig deep, but what if a single eventlog message is nailing the problem in a small clear voice?

If you visit the MSI SDK page, there is no “What’s New” section beyond version 5 which was released with Windows 7, so obviously there is nothing new in Windows Installer for Windows 8, right?  Nothing new for .MSI packages that is.  It has recently come to light in our labs that Windows Installer is secretly doing double duty to process the new Appx packages which are responsible for installing Windows 8 Metro WinRT Store Apps.  Why do I say “secretly”?