Also, unplugging your audio interface while Session is running can cause the auto-configuration of your audio hardware to malfunction the next time Session is launched, causing session to default to your computer’s built-in sound card, instead of your low-latency M-Audio hardware.
Unplugging your M-Audio USB audio interface (such as the FastTrack USB) while M-Audio's Session software is running may cause audio processing to fail when the device is plugged back in.