As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: A DIRTY SOCKS SMELL THAT STARTED DURING TAKEOFF AND CONTINUED THRU THE ENTIRE FLIGHT WAS REPORTED. MAINTENANCE ISOLATED THE SOURCE OF THE ODOR TO THE APU AND REPLACED IT PER TASK CARD 26L31049003. A SATISFACTORY LEAK/OPERATIONAL CHECK WAS ACCOMPLISHED.