I have had, and still have at time , issues with big crashes with Ableton, or with projects loading up so slowly as to actually never finish. Like robfill24 said I found, for me, the issue was something to do with my audio interface and so I guess the drivers in a roundabout way. I updated all my drivers for my Roland Duo-Capture EX but still had issue. I found I had a loose USB plug (running from my interface to iMac) in the back that wobbled ever so slightly and I had to use some tape to keep it in place. But even that did not help 100%. In the end I found I had to sometimes shut off my audio interface, let the samples load, then turn it back on. After I do that i tend to be okay, but this will not really help you in a live performance situation. You may wind up having to upgrade your audio interface to something that can handle what you are throwing at it, or upgrade all drivers and look for loose connections or broken cables. I know it can be a deal breaker to have it not work.