I got a “Data volume failed to mount” error earlier today, so I ran fsck -f /dev/sda4, and then rebooted. After rebooting, I get an OK Diagnostic, but the drive doesn’t show in the Network window on OS X, and even if I access the My Cloud directly (via Connect to Server), the only share that will mount is the Public one. All my other shares are not shown, even though they appear in the web UI and I can see and browse them via SSH. If I create a new share, it is visible through the Finder, but I can’t see any of the old ones. Any ideas on how to go about fixing this?
Try mapping the drive through AFP as a register user to see if it does the same.