USB dac not automically connected


I have an issue that I want to share with you:

I run Volumio on an Intel system, connected is a Meridian Director dac via usb. When the dac is switched on and I start the pc up, Volumio boots correctly but does not find the dac. Restarting the dac solves the problem. My work-around is to start Volumio first and after booting start the dac.

Is this a known problem?