I don’t have much more to suggest beyond what has been already suggested.
@iCloud, Here is what I (personally) would do in this instance. First I would try to reflash/reupdate the firmware using either the Dashboard (if it can be reached) or via SSH as explained/discussed in the following thread if the Dashboard cannot be reached:
https://community.wd.com/t/how-to-firmware-update-via-ssh/95476
Next, if the My Cloud unit is out of warrantee I would disassemble the My Cloud enclosure (perform an internet search for videos on how to remove the hard drive) to remove the hard drive, then attach that hard drive to a computer and boot that computer using a Linux boot disc or Live CD (Ubuntu is one popular Linux Live CD: http://www.ubuntu.com/download). From there one can use various Linux tools and command line commands to examine the hard drive and its contents. Further one could, if the data hasn’t been corrupted on user data partition (sda4), copy the data to another hard drive using the Linux Live CD.
Note that one should take care when using Linux to ensure they don’t trash their existing computer’s hard drive. Normally I disconnect or remove my computer’s existing hard drive(s) before working on the removed My Cloud hard drive.
If the My Cloud hard drive is corrupted and the data cannot be recovered (using various Linux data recovery tools/options) then I would attempt to “unbrick” the drive provided the drive itself is healthy (no bad sectors or SMART errors). One can search this subforum for various unbricking methods.
Or one could contact WD Support and send the My Cloud back to WD, pay them to recover the data (if possible) and repair/replace the My Cloud unit.
