After putting unit in sleep, MyCloud local window is stuck

This is a bit ridiculous and annoying.
My Cloud Mirror 2 Gen is setup properly with my iMac.
When in Tools, I click to put the unit on Sleep. After shutting down, my browser window remains stuck
on the dialog 'Wait until unit bla bla"
Only that the dialog never goes away and MyCloudMiror get stuck because it only remains active as the unit is on.
When it’s on sleep it freezes window.
To reinitialize, I only have one way : unplug mains and replug it.
As I said; ridiculous WD…
I tried with Safari and Opera : the same…
I’m on Sierra last update and WD firmware last update.

Hi,

Did you try performing a system only restore?

https://support.wdc.com/knowledgebase/answer.aspx?ID=14141

No use. By design, it seems, if you choose to put the unit to long sleep, it finally turns off, and you get that screen. Tested with 3 machines. Is your Mac behaving differently? I must add I set up the unit 2 days ago. Seems odd that system would already have a problem…

As I said, system reset didn’t change nothing. It’s by design, and it’s stupid : once you put unit to sleep and unit turns off (3 blue led off), MyCloud local windows is stuck… Talk about FUI.