I recently bought GPO4 with the Aria player, and have enabled all my tracks in one songs to play back through the Aria player. I'm writing for string orchestra, with one Audio track for the singer, and about 16 software tracks for the orchestra.. I have two tracks for each string player (ie, 2 for 1st violin, 2 for 2nd etc) each playing through a different Midi channel whenever possible. For each string player, one of the tracks is with an ensemble, the other with a soloist - this arrangement can give a realistic sound which I am pleased with. However, almost every time I start playback from anywhere other than the beginning, one or more tracks start to hang. The resulting cacophony has to be heard to be believed: but it's not funny after a while. You have to stop playback, and immediately start again -sometimes, not always, this fixes it, at least for a few bars. Starting from the beginning can also produce this problem, though not as frequently. This problem is so bad, that I'm thinking GPO4 is unusable in Logic. But surely this can't be so, or there would be umpteen complaints in the forum. I can't find any! I'm not at all technical, so if anyone out there is kind enough to help, I will be happy to provide any information that is needed. I'm running a 2 x 2.8 GHz Quad core intel Zeon Mac, with 8 GB of RAM and a 300GB hard drive.