Logitech MX Master Frequently Asked Questions Manual page 49

The connectivity range for your mouse is 10 meters (33 feet) from the Unifying receiver. Moving
the mouse closer will improve connectivity.
 +How to add a new Logitech device with Logitech Options
To add a new Logitech device:
1. Open Logitech Options.
2. If this is the first device to pair with your Unifying receiver, click Add Devices.
3. If you already have one or more devices paired, click Your Devices in the bottom right corner of
the window, and then Add Devices.