How to fix a garage door when it won't close?

To fix a garage door when it won't close, you need to identify cause, which is most commonly safety sensor issue, and apply appropriate repair to restore closing function. First, check if opener light blinks 10 times or clicks, indicating sensor fault. Safety sensors near bottom of tracks send infrared beam, and if dirty, misaligned, or blocked, receiving sensor blinks and opener refuses to close. Clean sensor lenses with soft cloth to remove dirt, cobwebs, or leaves, ensure sensors face each other with clear line of sight, and adjust by loosening wing nut and tilting until both LEDs solid, sending yellow and receiving green. Check wiring for loose connections at sensors and opener. Try holding wall button down continuously, as holding overrides sensors and forces close if sensors are issue, confirming diagnosis. If sensors are aligned and door still won't close, check close travel limit, as limit set too short causes door to reverse before floor, requiring adjustment of close limit screw on opener clockwise to increase travel. Check for door binding due to rollers off track, bent track, or broken spring causing force reversal, so try closing manually after pulling emergency release; if door binds or is heavy, spring or track issue needs professional costing 125 to 400 dollars. Ensure manual lock on track disengaged and lock mode on wall console unlocked by holding lock button. If opener hums but doesn't move, trolley may be disconnected or gear stripped. Unplug opener 30 seconds to reset board.