Unfortunately yes, it happened when I was running the drummer and changing presets.

Hi Silversax, Can I ask, was there much processing going on in the session, which would mean the error came up as a performance issue or is it similar to the issue i've been having, where the error message came up when logically it shouldn't. As I've had the message pop up many times, even on sessions where there is literally no plug ins or processing within the session, which makes me think it is not a performance issue but some bug in the way Logic deals with this issue.