As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CAPT SIDE SLIDING WINDOW MAKING LOUD SQUEAL AFTER TAKEOFF PRESSURIZATION NORMAL. GROUNDED - YES. DIVERSION TIME: 15 MINUTES. PRESSURIZED A/C AND VERIFIED LOUD SQUEAL FROM CAPT SIDE WINDOW. REMOVED AND REPLACED CAPT SLIDING WINDOW PER B737-800 AMM 56-12-11-000-801 AND 56-12-11-000-801 OPS CKECK NORMAL.