As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOUD SQUEAL IN FLT AND PRESSURIZATION PROBLEMS. RECEIVED CABIN ALTITUDE WARNING, PERFORMED AN EMERGENCY DESCENT AND DROPPED MASKS. LOUD SQUEAL NEAR MAIN CABIN DOOR. CLEANED AND LUBRICATED MCD SEAL IAW AMM. PERFORMED PRESSURIZATION TEST IAW AMM. OPS AND LEAK CHECKED GOOD.