As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA - AIRCRAFT RETURNED TO FIELD WHEN AFTER TAKE OFF THE AIRCRAFT DEPRESSURIZED AT 7000 FEET. MAINTENANCE INSPECTED THE AIRCRAFT AND REPLACED THE SNAP RING ON THE VENT DOOR SHAFT OF THE FORWARD CARGO DOOR. OPERATIONAL CHECKS WERE PERFORMED AND THE AIRCRAFT WAS RETURNED TO SERVICE.