Elecom M-IT11BR Series User Manual page 60

⑧ When using a USB Bluetooth receiver, change the connection on the receiver.
Depending on the specifications of the PC's USB port or USB hub, other USB 3.0 devices
used simultaneously with the trackball may generate noise that can worsen the 2.4 GHz
signal in the vicinity.
Examples of USB devices that may degrade the 2.4 GHz band signal
USB memory
Hard disk or SSD
Optical disk drive
Card reader / writer
LAN adapter
Others, all devices communicating data with a PC via USB 3.0.
You may be able to improve the situation with the following method.
Connect the Bluetooth receiver to another USB port away from other USB3.0 devices that
are in use simultaneously.
Connect the Bluetooth receiver to a USB2.0 hub or to an extension cable.