What are common garage door opener problems?

Garage door openers are complex electromechanical devices that can experience a wide array of common problems. The most frequent issue is a failure to close completely, which is almost always caused by misaligned, dirty, or obstructed safety photo-eye sensors located near the floor. If the opener motor runs but the door does not move at all, the main drive gear inside the unit is likely stripped and requires replacement, or the carriage trolley has been disconnected. Power issues are also extremely common; a dead remote control battery, a tripped circuit breaker, or a blown GFCI outlet can render the unit completely unresponsive. Sometimes, the door will open a few inches and reverse, which usually indicates that the close-force settings need adjustment or that there is excessive friction in the metal tracks. Flashing diagnostic lights on the main opener unit can often help pinpoint the exact internal electronic failure, such as a fried logic board resulting from a nearby lightning strike or a sudden power surge in the home.