I was just dealing with an escalated end-user problem with a production Silverlight application here at *nameless* Fortune 500:
User: I can't get your Silverlight app to install on my "new" Mac.
Support: What browser and OS version are you running.
User: I'm using Safari on a G5 tower running OSX 10 something.
Me: Um... The G5 is a PowerPC based computer. Apple announced their retirement in 2005, hasn't sold them since early 2006, and the current version of OSX doesn't install on them... And no, Silverlight doesn't run on them either...
I'm building a prototype Silverlight 4 application using the Silverlight Business Application template as a starting point (I chose this template so that I could get ASP.NET forms authentication working "quickly").
My test app worked fine in the development web server (aka Casini if you are old enough to remember that), but it didn't work in IIS.
Details from Saurabh's post: "WCF (and by association RIA Services) has a limitation that it does not support MultipleAuthenticationSchemas enabled in IIS. So if you are using Forms Authentication in your application (if you built your application using the Business Application template, Forms Auth is the default there) you need to make sure that for the IIS VirtualRoot that hosts your WebApp Forms Auth is enabled. Forms Auth + Anonymous will also work fine but Forms Auth + Integrated Auth is not supported."