My left knee makes a little snap noise when I do air squats. Apparently, this is not uncommon as I've found multiple posts about it in other forums. They say it's no concern if not accompanied by pain. I don't have any pain or soreness, but it's still a bit unsettling. Anyone else?
I had this for a few years after I had to haul ass for 10 miles when on an anti-poaching job in Africa carrying a far far too heavy load. "Crepitus" I recall, it got better by itself with swimming helping a lot I think. Years later I had a chance to play a monster extra on a TV show called Angel. A simple drop with some rigging was misjudged and I hit the ground hard while swinging sideways to the floor. Quite a twist. This time it did hurt and worried me, cracking loudly and easily. I had a week of rest using a pulley to give my legs traction (advised by an experienced stuntman) and again, it disappeared. As long as it is not arthritis, knees are very tough. Fish oil etc. probably would be a good idea and maybe some TENS with a physio however unless it is hurting it may be nothing.
'They' do say there's nothing to worry about, but I disagree. I think it could lead to long term problems. I would suggest doing the squats with a different stance, don't go down below where it 'pops' etc. Experiment a bit and see if you can avoid the pop. If that doesn't work, i would suggest a different exercise.
Just to be sure, may I assume that your knees don't go forward beyond your toes at the bottom of the movement, that your feet are always flat the ground, and that you push up mostly from the heels?
I forgot to mention that, as you go into both the bottom and top of the movement, with your feet ideally slightly wider than shoulder width apart, your knees should be perfectly aligned with the direction of your toes, which should be just slightly outward. I often see people do (weighted) squats where, as they start to push up from the bottom of the movement, their knees approach each other, closing the distance between them somewhat. That's not a good thing and something to be mindful about.