I've had several problems since the update.
1. In one project, I was using Session Drummer for a click track (don't want to argue about the Metronome right now). After the update, Session Drummer started playing back one of its canned MIDI sequences along with the click when I started to track, at very high volume. (This was compounded by my not being able to find the Synth Rack, but that's my fault for not reading the e-zine.)
2. While opening a project containing Rapture Pro, I got a message reading "Failed to locate resource", then a MS crash message (0xc...05). I uninstalled and reinstalled Rapture Pro, which seemed to fix it.
3. Trying to open some projects from the Start Menu or from the File menu led to "SONAR.PLT has stopped working". They opened OK from Windows Explorer, and behaved normally after saving.
I'm sure all this is going to get worked out.