Logitech MX Master Frequently Asked Questions Manual page 38

 +Unifying devices not detected after updating to macOS 10.12.1 Sierra
After you update from macOS 10.12 Sierra to macOS Sierra 10.12.1, Logitech Options software
may not detect supported Unifying devices on some computers.
To fix this issue, unplug the Unifying receiver and then plug it back into the USB port. If
Logitech Options still doesn't detect the device, you may also need to reboot your computer.
 +Check for Bluetooth Low Energy support
There are two ways to check if your computer supports Bluetooth Low Energy (also called
Bluetooth 4.0 or later):

Use Logitech Options Software to check

Check directly in the computer advanced settings (experienced users)
Use Logitech Options Software to check
You can use Logitech Options to find out if your computer supports Bluetooth Low Energy technology. If
you don't have Logitech Options software installed, you can download it.
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