As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED DUE TO: R2 WINDOW SHWOING DAYLIGHT AND IS EXTREMELY LOUD. AIRCRAFT AIR INTERRUPTED BACK TO AND LANDED SAFELY AT ORD. FOUND R2 WINDOW UPPER ROLLER OUT OF TRACK. INSPECTED WINDOW SEAL, ROLLS AND TRACK, PER AMM 56-11-00-200-803. NO DAMAGE FOUND. REINSTALLED WINDOW IN TRACK, PER AMM 56-12-11-400-801. WINDOW OPERATIONAL CHECKS NORMAL. PRESSURIZED AIRCRAFT AND NO LEAKS NOTED.