What are the common reasons why my garage door opener won't go up?

Common reasons why your garage door opener won't go up and open door include power issues, mechanical failures, and safety features that prevent operation to avoid damage or injury. The most common reason is broken torsion spring that counterbalances door weight, as when spring breaks, door becomes too heavy at 150 to 300 pounds for opener to lift, and opener may hum but not move or open a few inches then stop due to force overload, requiring professional spring replacement costing 200 to 400 dollars due to high tension danger. Power loss due to unplugged opener, tripped breaker, or GFCI tripped prevents operation, so check opener lights. Manual slide lock on door track engaged physically prevents door from going up and must be disengaged. Disconnected trolley from emergency release cord pulled disconnects door from opener, so motor runs but door doesn't move, requiring re-engagement by pulling cord toward door. Safety sensors misaligned or dirty with blinking LEDs can prevent opening in some models, so clean and align. Travel limits set incorrectly cause opener to think door already open. Door off-track due to hit or worn rollers binding prevents upward movement, requiring track realignment costing 125 to 300 dollars. Cable broken or off drum causes door to jam. Remote battery dead, lock mode engaged on wall console, or logic board failure also prevents going up. Try opening manually after pulling release; if door won't lift, spring likely broken.