Hi, you don't say whether you raise and lower your mainsail at the mast or from the cockpit. If it is from the cockpit, check all the turning blocks and deck organisers to ensure that all the sheeves turn freely, it's is surprising how much resistance just one stiff pulley can make, especially if it is so stiff, the halyard has worn a groove in the pulley! ( ask me how I know!) I replaced all my turning blocks with ball raced blocks and fitted new deck organisers last year for just that problem. The deck organisers were only three years old but at least one sheeve on each set ( 4 sets of triple organisers) had seized and could not be freed. They are about £22 each so I replaced all four and now make sure I lubricate them with dry lube or silicon spray as well as the mast track, every time I think of it. It has made a huge difference. The block I used were the Barton size 3 ball raced blocks in singles and doubles ( one of each on each side of the foot of the mast). I could never get the main to drop more than about 18" inches without then having to go to the mast and pull it down, it now drops at least 60% of the way on its own and just needs a light hand at the mast to drop the rest. ( 3/4 battened main). I have seen it advocated on other forums, to spray your mast slides with dry Lube, silicon or PTFE spray EVERY time you raise the main. Over time, it will deposit the spray higher and higher up the mast track and so ease raising and lowering. ( I do it when I remember to!)