As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HIGH PITCH SQUEAL FROM F/O SLIDING WINDOW, RTFL. SUSPECTED AREA OF SQUEAL IS FWD UPPER CORNER OF WINDOW. PUSHING ON WINDOW FRAME NO HELP IN ATTEMPT TO QUIET OR ALTER SQUEAL PITCH. REPLACED F-O'S SLIDING WINDOW PRESSURE SEAL. PRESSURIZED ACFT TO 4.5 DPSI, NO LEAKS NOTED, NO NOISE NOTED.