For some reason my USB3 external HD wasn’t being recognized by my NUC. I had a very old BIOS version, so I tried updating it, which solved the problem. Here’s how:

Search for the latest bios:
https://downloadcenter.intel.com/search?keyword=D34010WYK

In my case, it was this one. Download and save the .bio file in an USB key.
https://downloadcenter.intel.com/download/26632/NUCs-BIOS-Update-WYLPT10H-86A-

Open your NUC and look for the BIOS security jumper:

Read more “Intel NUC D34010WYK – Accessing and updating the BIOS”