Ready NAS not shutting down or rebooting - RN316

Hello folks in the community,

I cannot shut down my ReadyNAS gracefully.

Over the GUI it hangs on shutdown - the display  is showing  " Powering Off - Goodbye"

I also tried the hardware button method on the front of the RN - but again the display shows "Powering Off- Goodbye"

But the system doesn't shut down any further - it is stuck in that status.

What else can be done??

Running on OS 6.5.0 - but also had this issue under previous OS once or twice.

Update doesn't work over the GUI.

Is there another solution than pulling the AC Power Plug??

Starting the webinterface - I can still browse the shares but trying to reboot over the software I/O switch or the hardware button  on the frontpanel  won't work.

Any ideas ? Help greatly appreciated.