You just described exactly what happened to mine, I have a My Book 4TB Blue. I noticed one day the light wasn’t on. I check the outlet, made sure every thing was plugged in, and it was.
I tried accessing My Book from my PC, no luck. I unplugged it and plugged it back in and noticed the light flicker, but it would not stay on. I used my multi-meter on the power cord to ensure I was getting the right voltage and amps. It turn out that it is good. So, I did a little searching online for possible issues with My Books. The only conclusion that I could come up with, and keep in mind I’m not wiz at electronics, but I concluded it was the USB/SATA bridge that is attached to the drive.
Sense I am out of warranty anyhow I took the drive out of the case and attached it to my PC, as you would any hard drive. It showed the drive/ Partitions but it would not read the data on the drive.
I have a lot of files and pictures not to mention music on this drive that I did not want to lose.
Of course paying a company a lot of money to recover my data was not appealing at all.
I did how ever find a solution to recovering my data, now I have read that WD encrypts the data on there drives, which is why the drive/ partition showed up but could not read the data.
To make a long story short here is the solution to recover your data. I downloaded a free tool called “MiniTool Power Data Recovery” www.powerdatarecovery.com. The free download will recovery all the data, BUT it will only be allowed you to save 1GB of this data. I used the free download just to see if it would work and it did. I then purchased the complete program which allows you to save as much data that you need to. It coast about 70 bucks, to me that was worth it.
Yes I recovered all of the data that was on My Book. Now I have to figure out what I’m going to do with my 4TB drive.
One last thing, It took about 6 hours to scan my drive.