This thread helped me: http://community.wd.com/t5/WD-My-Cloud/Here-is-WD-My-Cloud-2TB-virgin-disk-image/m-p/668617/highlight/false#M5968
Got the image. Used Ubuntu and restored it to the drive. Scanned the ext4 partition - sda4 and extended and we’re back in business! 
This is what I did to fix it:
-load up a live Ubuntu drive and attach the WD drive to the machine.
-download the image from the link above and extract the IMG from there.
-start Disks application and select the WD drive.
-click on the gear and select ‘restore from image’ for the whole drive
-point to the downloaded image
-run fsck on the 4th partition
-for me, the device was mounted as SDA
- fsck /dev/sda4
-start GParted and extend the sda4 partition to fill up unused space
-put back in case and boot up
You now have a fully working drive in ‘just out the box’ condition.
