ProblemYou've fired up the shiny new Visual Studio 2015 (or an older version) to debug a Silverlight 5 application and you get an error: "You need to install the latest Silverlight developer run-time before opening Silverlight project". And in matters requiring a blog post, the go.microsoft.com link provided doesn't go anywhere.
SolutionMicrosoft, intelligently, gave up on Silverlight but there are still many projects that require it. My day job is Lync development and I needed this to troubleshoot a Lync CWE. All variations of the run-time are still available, but due to a security issue, they were moved to an obscure place... a security bulletin!
What you want is KB3162593 (updated to June 2016 patch), select Silverlight_Developer after clicking Download. Click the install link and you'll see Silverlight_Developer_Runtime.exe as an option. Be sure to uninstall Silverlight first, or you'll get an error. The 64-bit variant is there as well, along with the Version 5.0 SDK and others.
Woo Hoo! Time to party like it's 2011!
And in case you're looking for the Toolkit, it's still at its old CodePlex link.