Without some details, we can't help. So, what is the error calibre? Is the OS seeing the device? Is it mounting the driver properly? What OS? What firmware did the device upgrade to?
In any case, the two most likely reasons are you are running an old version of calibre from before the Glo HD was released, in which case you should update calibre. Or you Windows 10 machine has just updated itself and no longer supports the Kobo device. In which case, see
https://www.mobileread.com/forums/sho...d.php?t=276349.