Hi Pert,
And thanks for the reply. The link you supplied shows 4 changed files however i dont have one of those files in my Arduino IDE at all (samd21_usbdevice.h). I have checked the latest version (1.8.9) and that also does not have it - would there be any reason why that file is missing or is it for use with other arduino IDE's like Arduino Studio.
Any help is much appreciated.
Cheers.