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
OWIN
Are you really trying to add OWIN to your project or is this something unexpected?
In case you want to add OWIN, adding a Startup class is the way to go.
In case you don't need any reference to Owin:
delete Owin.dll from your /bin folder.
Owin.dll is the one trying to identify the Startup class.