Home › ASP.NET › Cannot create/shadow copy ‘DotNetOpenAuth.OAuth’ when that file already exists. – ASP.NET MVC4 Cannot create/shadow copy ‘DotNetOpenAuth.OAuth’ when that file already exists. – ASP.NET MVC4 Sunny Sharma ASP.NET ASP.NET MVC4 TroubleshootingJanuary 16, 2014 0 Share: facebook twitter whatsapp pinterest linkedin Error: Cannot create/shadow copy ‘DotNetOpenAuth.OAuth’ when that file already exists. How I solved it: Try to re-build the solution and it should work. It worked in my case, I’m not kidding !