OK, then… do you have a quality power supply, as the rPi3 will be less tolerant than the rPi2 when it comes to power. Even if the power supply can provide the 2A, another trap is the USB cable being used. Cheap cables have the thinnest of wires, where the voltage will collapse. The wire gauge for USB cables used on a rPi should be at least AWG 22.
Once you made sure all is working well, and you have no boot problems, try rewriting the SD card and start from scratch; if the error persists, you may want to post in the openHABIAN thread…
Good luck.