I haven't found a fix to this either. My Inspiron 15 5565 randomly stops recognizing my WiFi adapter at boot, and takes multiple reboots and BIOS resets to get it to be recognized again. Of course, my warranty had ran out just before I started experiencing this problem - I even switched to a different WiFi adapter and still have the same intermittent issue, reappearing almost every time I reboot my laptop. It seems like there's a bug in the firmware of this laptop that randomly stops WiFi adapters from being recognized by the system, Ubuntu still doesn't recognize a WiFi adapter when I reboot into it from Windows. Dell's built-in diagnostics don't pick up that the WiFi adapter is installed and state that the wireless switch is "off" - there isn't a wireless switch on this laptop, aside from the airplane mode button. My Bluetooth adapter, which runs off the same exact card, is always recognized by my laptop. Can someone from Dell chime in on this?