Sharepoint 2010 Convert classic to claim based authentication
26/11/2010 3 Comments
You already have a Web application created using Classic Mode Authentication and you want 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.Update()
Example:-
$App = get-spwebapplication “http://webapp:1907”
$app.useclaimsauthentication = “True”
$app.Update()
Warning!: This is an irreversable process.

I’ve followed these commands but I got “Attempted to perform an unauthorized operation” error during deployment process.
have you run PS as Administrator ?
Your sharepoint account via login on your machine is farm account or have priviledges of admin on sharepoint and local admin on your machine ?
Yes I’m the farm administrator
The commands were executed successfully but afterwards whenever I deploy a solution, I get error during activation of features on that web application.
P.S. After this problem occurred I found “http://technet.microsoft.com/en-us/library/gg251985.aspx” and followed its instruction but nothing changed.