Episerver manager fails to install any episerver version as a new site / virtual directory when you have .Net framework 3.5 installed (currently beta 1). Error message reads "Failed to register ASP.NET client scripts on this site" or something like that. The problem is EPiServer Manager likes to run aspnet_regiis.exe and tries to run that program from C:\WINDOWS\Microsoft.NET\Framework\v3.5.20404 , and since no such utility is shipped with .NET 3.5 it fails. Temporary solution is to move the v3.5.20404 directory elsewhere while installing and then move it back. Not the greatest solution perhaps but it worked on my computer. Björn Sållarp Avantime AB