Bouncing down in ableton 7

Been bouncing down my midi into audio within ableton 7. Sometimes when I do this the audio records no problem.... other times it doesnt record at all

Basically what im trying to find out is what is the exact process for when you record something. I basically want the recording to start and finish with whatever im recording starts and finishes, this doesnt always work like this so i need to go in and cut it at how i think it sits if ye get me

Some times its fine if its the likes of kicks cause i can then just go in and warp it no bother at all but when its off beat sounds its hard to warp because im unsure how it sits

Hope yous get what i mean, its a wee annoying factor for me thats been bugging for ages

any help appreciated :)