No, don't cut anything. You are talking about the lift cables that are used to lift your door up. Do as glennjanie says, and disconnect your door from the opener and see if you have smooth manual operation. Also, cycle the opener w/the opener disconnected and see if that runs smoothly too. Unplug the unit for a few minutes to reset any error codes. If it continues, there will be a flashing light to tell you what the problem is. Another possiblity could be that your springs need to be retensioned/rebalanced and/or the lift unit needs a strength adjustment at the unit. Finally, take the cover off and see if you can identify the nylon gears, inspect these for missing teeth. R&R as necessary.