This message was posted on behalf of Intel Corporation
I have same NUC model and I see the hard drive cylinder lighting up when hard drive activity is on,
I have top power button off and the front panel LED light on and this will be the normal behaviour of the NUC.
Please check for any grounding problem or contact your place of purchase for any warranty option within 30 days of purchase.
I believe that you mean that the HDD Activity LED is not working. If you wont the Activity LED to work when there is activity on HDD or SDD you shell mark it BIOS setteings:
1. While booting, depress F2 to enter BIOS setting.
2. Press on Advanced
3. Press on Devices
4. Press Sata
5. Sign V on HDD Activity LED and if you have M.2 SSD, on M.2 PCIe SSD LED
6. F10 to save and exit.
You can boot into BIOS from Windows:
1. Click on Windows icon
2. Click on Power icon
3. Shift + Restart
5. Advanced options
6. UEFI Firmware Settings
Any way, you shall update BIOS, the current version is 0051. You can download the latest version here: