Docking port and fingerprint reader

Hi, Can you help me? My Dell E6440 has some problems under Windows 10.

I bought 2 Dell E-Port docking stations, and after the firts dock when I turn on the computer or even if I restart it it shows me a dialog that I have to restart the computer because of some hardware change. It does not matter if the computer is on the docking station or not. After dialog come up I have to wait like 3 sec and the screen start flashing. It flashes 2-3 times, and after the last flash disconnect everything. USB devices, thekeyboard in the laptop, tocuhpad, and fingerprint reader. 
2 second later everything come back except the fingerprint reader, and I can not use the fingerprint reader. 
Dou you have any solution for this flashing? 

I have the A14 BIOS and the last downloadable drivers from the Dell support site. 

thanks, csaba