I have seen the many suggestions for the 'Error: ASP.NET Ajax client-side framework failed to load. ' problem and tried them with no success. What I haven't seen is anyone indicating the got this after installing Visual Studio 2012.
So, I am running IIS 7 and VS 2010 on my machine without problem. When I installed VS 2012 I started getting the above error. Same thing happens on 2 other developer's machines. If we uninstall .NET 4.5 and reinstall 4.0, it works again debugging from 2010.
As I said, I have searched for this problem and found many who have had the error under different circumstances. Tried a multitude of the suggestions, but have had no luck. Just wanted to see if anyone might have experienced the same problem or might have another suggestion based on my situation.