This may occur for one of the following reasons. Check these conditions and make the necessary corrections.
1. Unplug the USB cable, wait a few seconds, then reconnect it, making sure that the USB connection is firm.
2. Make sure that LEO has sufficient battery power. If the battery level is low, plug LEO into a wall outlet using the power adapter that came with it. To determine the battery level, go to LEO's Setup mode.
3. If your computer has recognized LEO in the past, make sure that you are connecting it to the same USB port. Unlike those of some other devices, the LEO software driver is port-specific. If you use a different port on the same computer, you will need to reinstall the software driver. To do this, refer to the Installation Instructions for LEO Software that came with your device.