Is this something recent? Or always been the case, but now more severe? Yes,lubricant can assist, but also before hoisting the main sail, use the topping lift or rigid vang to raise the boom high enough so that after the sail
halyard is tensioned, and the topping lift/vang is then slackened, the boom will fall down a few inches. (And obviously the main sheet needs to be slackened to allow the topping lift to raise the boom.) Doing this takes all the pressure of the weight of the boom off the sail when hoisting and allows the luff slides to remain much freer of tension and friction as the sail is raised. Its amazing to me that when I raise the boom like this, I can pull the main sail right to the top by hand. Conversely, if the boom is in a further down position, I can't. And then even some hard cranking in on the
halyard with my cabin top winch won't be enough to tension the lower luff enough to avoid the dreaded "scallop" look when the wind freshens during the sail.