I've received a replacement D54250WYKH NUC do to a failed 3.5mm audio jack. Intel sent a new NUC at the beginning of December to replace the old NUC with a bad headphone jack and I was able to transfer my drives Memory and WiFi cards. The new NUC has a functioning headphone jack and Windows transferred to the new NUC without any issues. But... In combination with these hardware manipulations, Windows 10 updated to the latest version. So... Windows 10 in this latest version appears to be rather unstable since my computer that used to run for weeks until there was a system update from Microsoft that required a reboot now won't run reliably for any time between 1 hour to a few days. The computer would reboot with no indication or blue-screen. All this instability has had me updating drivers endlessly. On December 26th the 2.5 inch SATA hard drive installed in the NUC disappeared and my applications crashed. So I thought I had found the problem with the computer. The hard drive wouldn't show up in the BIOS (when it was bad) and then when it shows in the BIOS and Windows boots it stays available for a random amount of time and then disappears. A backup copy of files that were copied and confirmed bit-for-bit accurate from the hard drive before the NUC was switched for the new one appears to show bit errors in files that should not have changed on the hard drive in the NUC. This was a Western Digital drive so I ran WD Diagnostics on the drive and it failed to successfully pass the tests. I felt this was a hard drive beginning to fail so I purchased a second matching hard drive and installed it in the machine a few days ago. I thought all was well but today (only the second day) the NUC is again unstable with the new hard drive. Upon seeing this, I found an external case and tested the hard drives on a different computer. Both Western Digital WD10JFCX hard drives pass the WD Diags on a different computer using an external USB to SATA adapter so I don't think the hard drives are damaged. Now I'm going to attempt to test the 2.5inch hard drive carrier in the NUC. I think I can swap with another NUC and see if the wiring in this carrier is bad. My fear is that the replacement NUC has a bad connection in the SATA interface circuitry.