https://www.dotnetzone.gr:443/cs/blogs/pkanavos/archive/2014/04/04/roslyn-visx-installer-crashes-with-system-uriformatexception-try-installing-as-administrator.aspxInstalling Roslyn on a machine where I had local administrator rights worked without issues. At work though, the installer crashed and the following event was logged: Fault bucket , type 0 Event Name: CLR20r3 Response: Not available Cab Id: 0 ProblemelCommunityServer 2.1 SP3 (Build: 20423.1)