I'm a newbie to Sonar, and I've just installed both X1 and - although a couple of days later - X2. While I'm quite happy with X1, X2 has a fatal tendency to crash as soon as I open a project. Therefore, I keep working with X1 - and X2a didn't help... I hasten to add that X1 was installed from the DVD, and I don't remember being asked to choose a version. I was asked when I installed X2, though, and I went for the 64bit. I wonder if that was a good idea...