As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 8049 - IAD - CREW REPORTED RECEIVING A LANDING GEAR LEVER DISAGREE MESSAGE ON THE EICAS AFTER THE GEAR WAS SELECTED UP AND THAT THE LEFT MAIN DID NOT RETRACT. MAINTENANCE INSPECTED THE AIRCRAFT AND REMOVED AND REPLACED THE NR 1 MLG UPLOCK BOX, THE BOTTOM PROXIMITY SWITCH ON THE NR 1 MLG UPLOCK BOX. SYSTEM OPS CHECKED GOOD FOLLOWING REPAIRS.