Disconnecting a device
Most USB devices can be removed and unplugged. When unplugging storage devices, such as USB flash drives, make sure that the computer has finished saving any information to the device before removing it. If the device has an activity light, wait for a few seconds after the light has finished flashing before unplugging it.
If you see the Safely Remove Hardware icon

in the notification area on the right side of the taskbar, you can use this as an indication that devices have finished all operations in progress and are ready to be removed. Click the icon and you'll see a list of devices. Click the device that you want to remove. Windows will display a notification telling you it's safe to remove the device.
Note
You can also safely remove devices from the Computer folder. Click the Start button

, click Computer, right-click the device you want to remove, and then click Eject.