Why does my garage door only open a few inches and then stop?

A door that opens only a few inches and stops is almost always tied to the spring system. A broken torsion spring means the opener no longer has enough counterbalance to lift the door's full weight, so it strains for a moment and gives up. Other possible causes include a misaligned photo eye sensor near the floor or limit settings on the opener that need adjusting. Because torsion springs hold a lot of tension, this is not a safe repair to attempt yourself. A technician can diagnose it quickly and safely.