VS2010 web setup project needs IIS6 (metabase) compatibility on IIS7. Consequences or other issues for the application?

Question

When trying to install a web setup project (MSI) created in Visual Studio 2010 on Windows Vista, Windows 7 or Windows 2008 Server the setup will fail, with some generic error. According to http://devio.wordpress.com/2011/04/26/pitfalls-installing-web-setup-msi-on-iis-7/ this is because of a compatibility problem between the setup project en IIS7.

To resolve this I've to enable/install IIS6 metabase compatibility in my windows configuration. This workaround did fix the problem, but raises 2 questions:

• Does this have any (negative) impact on functionality of IIS 7?
• How can I notify a user running the installation of this problem so he or she can take proper action and install the metabase compatibility component? Is it possible to pop-up the windows component configuration dialog from this install, to make life easier for the user?

Answer 1

1. I don't think this will have any impact on the application itself, as long as it's implemented the way to talk to IIS7 via its native API. Otherwise, if it doesn't support IIS7 you'd have to enable IIS6 compatibility anyway.
2. The standard approach to search for anything on a target machine is searching registry and file system. I don't know how it is possible in VS setup project, but e.g. WiX has special elements for this (RegistrySearch, DirectorySearch, FileSearch). Basically, this post to WiX Tips and Tricks thread shows how to check for IIS6 compatibility in WiX and block the installation if it's not enables/installed. It's rather straight-forward even if you don't know WiX, but know the concepts of Windows Installer, and it can help you translate the code into the similar thing in VS setup project.

Answer 2

We seem to be having one negative impact on our servers. Everytime we roll out a .NET 4.0 application with a msi made in Visual Studio, We get a recycle of ALL our application pools, even the ones not affected by the install. Apparently the root cause of this is the IIS 6 compatibility. ( This was reported to us by a developer of microsoft in response to our support question about this.

At the moment we have no solution. It's impossible to convert all our installers to Wix.