Cause analysis
Because the current smartphone connection computer needs to turn on the USB debugging mode before it can be used to connect the computer properly so we need to operate.
Solution One, turn on the USB
1. Open "Settings"--"all settings"-"about mobile phone"-"Android Version", Continuous click "Android Version" 5 times, the phone will be prompted several open development mode.
2. This time return to the Settings page at the bottom you will see "Developer Options", click on the "USB debugging" switch.
Cause analysis
There is also a possibility that USB turned on successfully, but found that the computer still does not recognize the computer so we can see if the phone driver is installed, step: The Desktop, right click on "My Computer" and then click "Device Manager" here to find the Android icon driver to see if there is? Number or exclamation mark, if we download a 360 assistant to it to install the driver can be resolved.