System: Ubuntu 18.04 64 - bit operating system

Before the hard drive connected to the computer, the desktop will automatically pop up hard disk or usb logo, main folder will display name of mobile hard disk or U disk, but then there was a time I don't know the reason why not, then don't know how to make good again, but this also not line, online also didn't find a solution, which a great god, please grant instruction! thank you