Lenovo IdeaPad U165 User Manual page 61

The connected external
device does not work.
Do not connect or disconnect any external device
•
cables other than Plug and Play (PnP) device while
the computer power is on; otherwise, you might
damage your computer.
When using a high power consumption external
•
devices such as an external USB optical disk drive,
use external device power adapter. Otherwise, the
device may not be recognized, or system shut down
may result.
Chapter 5. Troubleshooting
47