Apparently during the upgrade Windows 10 installs the Broadcom Bluetooth 3.0 USB, which is incorrect for the Logitech mini-transmitter and will not start.
First, download and install the latest version of SetPoint from Logitech [6.67.82_64]. Then under Device Manager uninstall the Broadcom Bluetooth 3.0 USB. Unplug the Logitech dongle, if not done already. Then, with SetPoint opened, plug the dongle back in to an available USB port.
From docstork via https://forums.logitech.com/t5/Keyboards-and-Keyboard-Mice/Windows-10-and-Broadcom-Bluetooth-3-0/m-p/1428404/highlight/true#M56703