If you run /examples/14-WiFi-Shield/mjpeg_streamer.py from the IDE and if you stop it while it is Waiting for connections…, then you cannot eject the M7 from its USB connection. I’m testing it on mac with OSX 10.10.5. The M7 is running with the latest firmware and the WiFi shield.
What do you mean by eject it from its USB connection ? Do you mean reset the camera ?