Information
Ensure no device is connected to a virtual machine if it is not required. For example, floppy, serial, and parallel ports are rarely used for virtual machines in a data center environment, and CD/DVD drives are usually connected only temporarily during software installation.
Solution
From the vSphere Client, right-click the Virtual Machine and go to 'Edit Settings'.
Select the USB controller, click the circled 'X' to remove it, and click 'OK'.
or
From a PowerCLI command prompt while connected to the ESXi host or vCenter server, run the following command:
Get-VM 'VM Name' | Get-USBDevice | Remove-USBDevice
Note: This will not remove the USB controller, just any connected devices.