InstallAware

That's a very clever workaround, great job!

I also stress once again you were not experiencing a freeze but a wait for the Windows Installer mutex, which is being held by the process that started the MSI transaction, as separate from the process attempting to uninstall the product.

Thanks. True, it's not a freeze but rather a deadlock. To the end user, the deadlock manifests as a freeze, a hung installer. Semantics aside, this bit of clever scripting should allow us to meet both requirements - that the upgrade occurs in a transaction and that the old version's MSICode is executed when removing it.

This is actually more than semantics...the deadlock is created in your own coding. It is what one would call a logical error in programming