Steps to Reproduce

1. Install JIRA 6.3.14;
2. Hide the 'Priority Field' in the Default Field Configuration;
3. Install JIRA Service Desk 2.2;
4. Click on 'Service Desk >> Create Service Desk';
5. Select "New Service Desk Project";
6. Try to create it.

See this demonstration Video: error-create-sd.mov

Expected Behavior

The Service Desk would be created.

Actual Behavior

The following error is displayed:

Workaround

Navigate to Administration >> Issues >> Field Configuration >> Default Field Configuration and click on 'Show' next to the Priority field.