Safety: Garage doors are heavy and spring/cable systems can be under significant tension. Do not loosen or disassemble high-tension hardware unless you are qualified to do so.
Note When It Reverses
A door that reverses near the floor suggests a different set of possibilities than one that changes direction immediately after starting.
Check for Mechanical Resistance
Binding rollers, damaged tracks, or an unbalanced door can affect how the opener senses movement.
Safety Systems Matter
Do not bypass safety features to keep the door moving. The correct repair is to identify why the system is reacting.