Please do a forum search for “sleep”. You’ll find that the sleep issue is a well known problem with the My Cloud and you’ll find various suggestions to try. For many the My Cloud, in default configuration with the Sleep option enabled via the My Cloud Dashboard, simply doesn’t sleep for long periods of time. Instead the device wakes up every 8 to 10 minutes if not earlier.
There are a variety of options, almost all involve using SSH to disable or modify certain services within the My Cloud Firmware, to try and get the device to sleep for longer periods of time. Among the options are stopping “wdmcserverd” and “wdphotobmergerd”.
It should be noted that the My Cloud is designed to be running 24/7. It remains to be seen how this inability to sleep affects the “health” of the internal hard drive within the My Cloud.
See my post in another thread for a number of threads on this sleep issue and things to try:
https://community.wd.com/t/wd-my-cloud-4tb-harddisk-keep-running/161358/2
