Unit doesn't turn on

I have the WD TV LIve updated to latest firmware (non beta).

I’m using the remote to turn off the device (front led is off).

Many times, on the following day, I can’t turn on the unit from the remote or from the web interface.

No matter what I try, the led is off and there is no output display.

Unplugging/plugging the power cord reboots the unit and it starts to work again.

Any idea?

Sometimes, after upgrading or downgrading firmware, it is necessary to reset to factory defaults. Go into the setup and choose System, then reset to factory defaults. You will have to enter all of your setup information again, but resetting to factory defaults sometimes fixes problems like you are seeing and is worth trying.