No sleep MBL duo working with iMac

Happy new year and al the best to all of you

I need some help regarding the following issue. My iMac is working with a MBL duo, router fritzbox 7390 and some other devices in a LAN. The NAS is timemachine made backup and makes music files available for sonos streaming. 

DNLA is not active, itunes the same, no remote access and no apps in use from WD.

If iMac is power off, the NAS is going to sleep as described in manual. Turned on it takes a few minutes and the NAS reports duty. Some minutes later it goes down and will start running again. 

Please, is there any idea?

Happy new yea!!!

Check if the Energy Saver option is enabled on the my book dashboard. Check page 63 of the manual for more info.


done before and no effect on this issue.

In one of the .log files elsewhere on the mac I found something like ‘mediascawler wake …’

Could this process be reason of the Problem? Can I stop it?

Another question linked to the log files. Where do I find these files of MBL and how to open?

Sorry for my way of asking but I am no expert in edp and no specialist in English language. 

When I turn on my iMac, the mybook live duo also turn on. Then after a while it turn off. Then it turn back on. Even tho no one is using the ddrive. Anyone knows why?