title: Errors after PFUser logOut and PFFacebookUtils logInInBackgroundWithReadPermissions
body: <p>I migrated my iOS code to FBSDK v4 + Parse 1.7.1 and I'm trying to handle the case of linking a user to a FB ID but it's already linked:</p>
  
  <pre><code>Another user is already linked to this facebook id. (Code: 208, Version: 1.7.1)
  </code></pre>
  
  <p>Everything seems to work fine after user logout and FB login but every time I alter or save the current user, or query a table, I get various errors such as:</p>
  
  <pre><code>Parse::UserCannotBeAlteredWithoutSessionError (Code: 206, Version: 1.7.1)
  
  "PFKeychainStore" failed to set object for key 'currentUser'
  
  no results matched the query (Code: 101, Version: 1.7.1)
  </code></pre>
  
  <p>Here is my code:</p>
  
  <pre><code>NSArray *permisions = [NSArray arrayWithObjects:@"public_profile", @"email", @"user_friends", nil];
  [PFFacebookUtils linkUserInBackground:[PFUser currentUser] withReadPermissions:permissions block:^(BOOL succeeded, NSError *error) {
  
          if(succeeded &amp;&amp; !error) {
              //... use data
          }
          else {
              if(error.code == 208) {
                  [PFUser logOut];                   
                  [PFFacebookUtils logInInBackgroundWithReadPermissions:permissions block:^(PFUser *user, NSError *error) {
                     //here I get a valid user and no error but...
                     //after this point the errors mentioned start to show up
  
                  } 
  
              }
              else
                  //... handle other errors
          }
  
  
      }];
  </code></pre>
  
  <p>I use Parse's automatic user until a user is linked to a FB account.</p>
  
  <p>Would love some help about this, thanks!</p>