Webforms. It seems to be using IIS Express, for both version I simply use the nice GUI |> Debug command but it seems they might do different things from VS2010 to VS2012... VS2010 opens a development server, VS2012 opens IIS Express, how can I get VS2012 to do the same thing as VS2010 to test my website?
Btw I'm targeting .NET 3.5 so I don't think .NET 4.5 should affect my app, since it's not .NET 4...
Solved it! It was definitely IIS Express giving me trouble, went into Project properties and changed it to use VS local dev server and it works as expected now. Thanks for leading me in the right direction