My WD Passport was not power on from stand by when PC turned on

my WD passport essential SE goes to stand by after 30min if idle but when the PC is turned on the HDD was not power on and I cant see this in my computer.  I must unplug the USB cable and connect it again to see the unlock cd-rom and enter password of my HDD to see the external drive.

are you have any answer to solve this problem?

You can try turning on Auto Play on your Computer. Also some computers keep sending power trough usb thus not allowing the drive to “wake up” when on hibernation. 

Make sure drives firmware and software is up to date. And check the autoplay and see how it go’s.

I’ve found info about similar problems on this  here