I had it...
Just download the last version, disconnect your ROG from the internet, use the DDU uninstaller utility and remove your actual version, restart and install the last version.
The Nvidia Geforce Experience is just buggie. I've never been able to update from it, always get me error in some way...
P.S.: Link for the DDU uninstaller utility:
http://www.guru3d.com/files-details/display-driver-uninstaller-download.html