here's something I fished off the logitech website:
https://forums.logitech.com/t5/Logitech-G-Mice/LGS-not-detecting-G502-Proteus-Core/td-p/1283850
Describes your issue I believe.
The TL
![:D :D](/images/Smileys/biggrin.gif)
Go to the program files logitech software /fwupdater ,and look for the standalone firmware update exe file.
Run that.
Then follow the instructions.
Mouse should be back to normal.
Other possible solution:
First download drivers 8.55.137 (can be found at: http://www.touslesdrivers.com/index.php?v_page=23&v_code=42150)
then:
1) Go to Control Panel
2) Go to Devices and Printers
3) Under devices you should see "Gaming Mouse G502" along with a bunch of other stuff.
4) Right click the G502 icon, and pick "Troubleshooter"
5) Let the troubleshooter do it's thing. It should detect that there is no driver, and then find and install it correctly.
6) Start up the logitec software and it should be working now.
See if it helps you out.
-Durkalina