Do you have the bag on the bike or off? The reason I ask I just replaced a lid on my left bag because I put a scratch on the old one anyway I replaced the lid on my living room floor tried to latch it it wouldn't checked it several times couldn't see anything wrong, compared it to the right side looked the same, took it back apart tried unsuccessfully again, finally on the third try I had my wife assist in holding the bag while I tried to latch it, it latched perfectly she ask whats the problem, not what I wanted to hear at that time my patients where a little thin. I took the bag out to the garage and installed it back on the bike it latches every time perfect, I guess I wasn't holding my tongue right lol