Power failure, and since then, I cannot access WD MyCloud which was mounted in Mac’s Finder.
Can’t access through the WDMcloud app and worse still, it looks like I’ve lost an awful amount of data that I had saved on it. Isn’t much I haven’t tried, though I am no IT expert but any advice would be much appreciated! 
It is very unfortunate thing to happen. I would recommend you try the link below:
https://support.wdc.com/knowledgebase/answer.aspx?ID=17150&lang=en
