Question: We have a problem with our iPhone-simulator that was caused by using this line:

```
    Foo = [NSURLCredential CredentialWithUser:foo 
    password:bar persistance:NSURLCredentialPersistencePermanent];

```

The problem was created when the credential was given to the challenge over at

```
        -(NSURLConnection *)connection
        didReceiveAuthenticationChallenge(NSURLAuthenticationChallenge *)challenge
    {

        [[challenge sender]useCredential:Foo forAuthenticationChallenge:challenge]      
    }

```

So now when we run the application, we dont ever ever again run into the authenticationchallenge again, which is quite odd, even if we change the credential to

```
    Foo = [NSURLCredential CredentialWithUser:foo 
    password:bar persistance:NSURLCredentialPersistenceForSession];

or even

    Foo = [NSURLCredential CredentialWithUser:foo
    password:bar persistance:NSURLCredentialPersistenceNone];

```

To summarize:

By using credentialpersistencepermanent the credential is somehow saved somewhere and used automagically to access wherever we need to autenticate ourselves. 

So for testing-purposes, we would really like to remove this persistent... credential. 

Any ideas anyone? :)

Answer: 
Have you tried just resetting the simulator? It's in the Simulator menu.
It's saved in the keychain. To go from `NSURLCredentialPersistencePermanent` to a less permanent state like `NSURLCredentialPersistenceForSession`, you have to remove it and recreate it.

Note that in some versions of the tools resetting the simulator does NOT clear the keychain.