I have an Intel NUC NUC5i3RYH that is having a peculiar problem. Here are the details.
1. Intel NUC NUC5i3RYH
2. One Internal Seagate 1 TB Hard Drive - OS is installed on this.
3. 16 GB RAM - 8 x 2 GB SO-DIMM's - Crucial
4. Two External USB 3.0 WD 2.0 TB drives connected to Rear USB Ports. Both are data drives, no boot partitions on these. These are both WD's but two different models.
5. USB Mouse and Keyboard - Connected to front USB Ports
Symptoms: The system is working fine except when cold rebooted. After a cold reboot the NUC goes into an indefinite boot loop. I just see the NUC Logo and then it reboots after a few seconds. Cannot enter the BIOS since the F2, F7 etc message does not appear on the bottom right of the monitor. The keyboard and mouse are unresponsive.
Procedure to boot: Unplug both the external hard drives and reboot. The system proceeds to boot normally. Once booted, I can then plug in the two external drives and they appear to work fine. A warm reboot causes no problem and the system works properly and boots up just fine.
Things tried to resolve the issue: Tweaked all the BIOS settings like, UEFI Boot -> disable/enable, Watchdog -> disable/enable, USB xhci mode -> disable/enable and many other parameters as discussed throughout the forum. However the problem remains. I am running the latest BIOS as well. Version RYDBWi35.86A dated 1/18/2017.
Other Observations: Have tried powering up the external USB drives with a powered USB hub which has no effect, the system still goes into a boot loop. Also noticed that when the drives are attached the keyboard and mouse become unresponsive. It seems as the whole USB bus is hung till I remove the external USB drives. If I remove "both" the drives during the boot loop, I immediately get a message on screen saying that POST has failed and I could either press F2 to go into BIOS or F9 to continue. The keyboard and mouse come alive at this stage and I can press F2 to go into BIOS and start twiddling my thumbs . Last point, I did install this system using a 16GB Pen drive so apparently pen drives may be working after a cold reboot. I think the issue is with the two external drives plugged in.
Would appreciate if Intel support can look into this matter and provide a resolution. Would be happy to provide any more details as required.