The strange case of VisualStudio.DTE.9.0 registry key missing for Visual Studio 2008 Professional

The other day I received a bug report from a customer of my MZ-Tools 6.0 add-in because the setup was not detecting any installation of Visual Studio while he claimed that he had Visual Studio 2008 Professional. The setup of that version of MZ-Tools detects the installation of Visual Studio versions checking the existence of the registry entries HKEY_CLASSES_ROOT\VisualStudio.DTE.<version>, where <version> can be 8.0 for VS 2005, 9.0 for VS 2008, etc. It does so because those entries are not created for Express editions of Visual Studio, which in turn don’t support add-ins.

So, I asked the customer to check the existence of HKEY_CLASSES_ROOT\VisualStudio.DTE.9.0 and he informed me that the registry key didn’t exist, while it should because Visual Studio 2008 Professional creates it. In the next e-mail he mentioned the “educational” version of Visual Studio 2008 Professional. I was not aware of this edition, but I found that there is a Microsoft Education Product Center that offers licenses for “academic” institutions. I don’t know for sure if the “Professional” edition of Visual Studio is different for academic institutions and for companies, but there is another registry key that can be used to detect if Visual Studio is installed:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\VisualStudio\<version>

My customer confirmed me that that registry key did exist. My only doubt was if Express editions create those too so I searched the web and I found my own article (I always love when this happen) HOWTO: Detect installed Visual Studio editions, packages or service packs that states that Express editions don’t create:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\VisualStudio\<version>

but:
  • For VB Express: HKEY_LOCAL_MACHINE\Software\Microsoft\VBExpress
  • For VC Express: HKEY_LOCAL_MACHINE\Software\Microsoft\VCExpress
  • For C# Express: HKEY_LOCAL_MACHINE\Software\Microsoft\VCSExpress
  • For J# Express: HKEY_LOCAL_MACHINE\Software\Microsoft\VJSExpress
  • For Web Developer Express: HKEY_LOCAL_MACHINE\Software\Microsoft\VWDExpress

So, future versions of my setup will use HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\VisualStudio\<version>.