I\'m getting this error as my project is not able to find the reference for OWIN
startup class. I\'ve even installed all the OWIN reference packages through Nug
In my case, I had renamed the project and changed it's folder structure. I found that updating the RootNameSpace and AssemblyName in the .csproj file where the error was being thrown resolved the error. If you have modified paths of your project I'd recommend checking this as well.
Company.Product.WebAPI
Company.Product.WebAPI