When using the Windows Identity Foundation and following a tutorial in Vittorio Bertocci’s excellent book ( Programming Windows Identity Foundation ) I discovered a problem with the way that the WIF installs.
When you right-click on an ASP .NET project to “Add STS reference” the option doesn’t come up. Upon further inspection it turned out that it didn’t even appear under Tools->Add-In Manager.
When looking for a fix for this problem I found several things that didn’t help my circumstance – including logging in as a non-domain admin! However it turns out that you can’t have the two versions of WIF (v3.5 and v4.0) installed side by side.
The fix I found was to uninstall v3.5 (I was working against vs2010 and v4.0 of the .NET framework – otherwise uninstall the other one) and then Repair the installation of the one you are using. This should (upon restarting Visual Studio) mean that the add appears under Tools->Add-In Manager and also as an option to add the relevant reference to an ASP.NET project.