How to fix a garage door that won't close?

To fix a garage door that won't close, you need to diagnose most common cause which is safety sensor issue, and then address travel limits, force settings, and mechanical binding that prevent closing. First, check safety sensors near bottom of door tracks, as dirty, misaligned, or blocked sensors with blinking LEDs are most common cause of door not closing, so clean lenses with soft cloth to remove dirt and cobwebs, ensure sensors face each other with clear line of sight, and adjust by loosening wing nut and tilting until both LEDs are solid, typically sending yellow and receiving green for LiftMaster. Check wiring for loose connections at sensors and opener unit. Check for sunlight shining into sensor causing false blockage and shade if needed. If sensors are solid but door still won't close, check travel limits, as close limit set too short causes door to reverse before touching floor, requiring adjustment via limit screws on opener. Increase close force slightly if door reverses due to thinking it hit obstruction. Check for door binding due to rollers off-track, bent track, or broken spring by trying to close manually after pulling emergency release; if door binds, call professional costing 125 to 300 dollars. Check if lock mode engaged on wall console. Try holding wall button down continuously, which overrides sensors and forces close if sensors are issue. If sensors damaged, replace costing 20 to 50 dollars DIY or 100 to 200 dollars professionally. Regular maintenance like cleaning sensors and lubricating rollers prevents closing issues.