I recently got involved into an issue where launching the Dynamics AX 2009 Client causes the Windows Installer to start and requesting a Microsoft Axapta 3.0 installation source.
Actually Microsoft Axapta 3.0 was installed on the system before but it got uninstalled when Dynamics AX 2009 was installed. This issue mainly occurred when the Dynamics AX 2009 Client was launched with a AXC configuration file.
The reason for this was an existing file mapping to AXC files, that is created by Microsoft Axapta 3.0 in the Windows Registry. This file mapping is added by Microsoft Axapta 3.0 but it is not removed when uninstalling. And Microsoft Dynamics AX 2009 is not updating it as Dynamics AX 2009 is not longer adding the file mapping at this place.
To make a long story short, the file mapping created for AXC files was still pointing to Microsoft Axapta 3.0, firing up Windows Installer as Microsoft Axapta 3.0 was already uninstalled.
We were able to solve this issue by manually removing the file mapping for AXC files from the Windows Registry. The Registry Keys we had to remove were: