title: Parse: Unauthorized when querying ParseInstallation
body: <p>I have this code to query an installation by <code>uniqueId</code> custom field in <a href="http://www.parse.com" rel="nofollow noreferrer">Parse</a>:</p>
  
  <pre><code>public static void init(Context context) {
      Parse.initialize(context, Constants.PARSE_APP_ID, Constants.PARSE_APP_KEY);
  
      String wifiMacAddress = getWifiMacAddress(context);
  
      ParseQuery&lt;ParseInstallation&gt; query = ParseInstallation.getQuery();
      query.whereEqualTo("uniqueId", wifiMacAddress);
      query.findInBackground(new FindCallback&lt;ParseInstallation&gt;() {
          @Override
          public void done(List&lt;ParseInstallation&gt; parseInstallations, ParseException e) {
              if (parseInstallations == null)
                  throw new RuntimeException(e);
              Log.d("prova", "Size: " + parseInstallations.size());
          }
      });
  }
  </code></pre>
  
  <p>But I get a <code>ParseRequestException</code>:</p>
  
  <blockquote>
    <p>java.lang.RuntimeException:
    com.parse.ParseRequest$ParseRequestException: unauthorized</p>
  </blockquote>
  
  <p>I'm using the Parse master key. If I use the client key instead, I get this error:</p>
  
  <blockquote>
    <p>java.lang.RuntimeException:
    com.parse.ParseRequest$ParseRequestException: Clients aren't allowed to perform the find operation on the installation collection.</p>
  </blockquote>
  
  <p>What am I doing wrong?</p>