As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOUD SQUEAL F/O SLIDING WINDOW FL260 CABIN ALT 4250. STOPPED FL130 CABIN ALTITUDE 2650. PROBLEMS RECURRED ON FLT 166-19 CAUSING DIVERSION TO DEN. FOUND AFT ROLLER OF FO WINDOW OUT OF ADJUSTMENT. ADJUSTED FO WINDOW AFT ROLLER PRESSURIZED A/C WITH NO NOTED PROBLEMS. NO REPEATS SINCE ORIGINAL.