As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB, AT APPROXIMATELY 15,000 FEET, THE FLIGHT CREW RECEIVED A RIGHT THRUST REVERSER UNLOCKED CAUTION MESSAGE. THE CREW COMPLETED THE APPROPRIATE CHECKLISTS, DECLARED AN EMERGENCY. THE FLIGHT RETURNED TO ORD AND LANDED WITHOUT FURTHER INCIDENT.