Both my boss and I encountered this problem today in both of our Logic Setups. The EXS instruments randomly stoped working. They were still loaded, but would not play back any of the samples for any instrument loaded, re-loaded or new exs track. If we went into the editor for the instrument, and played on the virtual keyboard, the sample would not sound either. The only way we could get anything to work, was by editing the sample within the exs editor and playing it back. After doing the individual sample playback, all the exs insturments would work again. BUT as soon as we hit playback button for the session, all the exs instruments stopped working. I should mention that the other AU instruments we had loaded still worked, and the midi routing we had to our PCs worked as well, so it was not a problem with the audio driver, or "zero-ed" controller problem. We re-booted the system and loaded the same session and it played back just fine. They both seem to be working at this point. This machine is a dedicated Logic Machine, there is no other software on it, other than Native Instruments, and various other plugins. The Two Systems: G5 8gbRam 2ghz OSX 4.7 Logic 7.2.2 RME FireFace800 MacBookPro 2ghz, 2gbRam OSX 4.8 Logic 7.2.3 M-Audio 410 Please let me know if you've had this problem as well and if there is anything we can do to fix it. Thanks.