What if you already have a Web application created using Classic Mode Authentication or How to convert Web application from Classic Mode authentication to Claims based Authentication?

You don’t have to delete that web application. You can convert that web application from classic mode authentication to claims based authentication. However this can only be done using PowerShell and it’s an irreversible process. Follow PowerShell commands to convert the web application from Classic Mode Authentication to Claims based Authentication:

$App = get-spwebapplication "URL"

$app.useclaimsauthentication = "True"



$App = get-spwebapplication “http://FBA:1907”

$app.useclaimsauthentication = “True”