You can still run Logic in 32 bit mode on a 64 bit system. Same with Ableton. This website is pretty handy --> http://roaringapps.com/ According to this, if you download and install the latest updates for logic pro 9 straight away, logic works OK. Unfortunately there is no data on ableton on the above site, but according to ableton, it works on yosemite https://www.ableton.com/en/help/article ... patibilty/ I suggest checking plugin compatibility too