Cannot connect USB Drive to MyCloud

Hello all, I hope you can help…

I have recently bought a WDMyCloud 4TB device and I love it. However, I have tried connecting a USB drive to expand the storage etc and every USB drive I try will NOT show up as a Share! Does anyone know why this is?

I have tried restarting the MyCloud device but with no success. Any help would be very much appreciated.

Thanks in advance

Scott

Is your USB drive formatted? Which format? NTFS?

When you look at the NAS UI, on the top right tere is an icon with a USB symbol. Is it lit up? When you click on it, does it show your USB disk?