This is my answer at: http://stackoverflow.com/questions/31552082/vsix-installer-signaturedescription-could-not-be-created-for-the-signature-algo/ to the question on why some extensions fail to install at RC (Release Candidate) versions of Visual Studio 2015, showing error “SignatureDescription could not be created for the signature algorithm ...

Recently, to save myself sometime after having renamed some interfaces/classes in the ClipFlair project sourcecode, I right-clicked one of the class diagrams (.cd files) in it at Visual Studio’s “Solution Navigator” (this is an enhanced Solution Explorer addon) and using “Open With…” I opened up the diagrams with the XML editor to do a rename-all ...

I just had some big trouble troubleshooting the Visual Studio / XAML compiler error message: The tag XXX does not exist in XML namespace ‘clr-namespace:YYY’ It turned out this occurred because I had a Silverlight library with Assembly name X and default namespace X (at properties pane), but was using it from a demo project [...]