The motherboard manufacturer. I agree the problem is involved. That is you have a lot of moving parts and it doesn't tell you what one it is.
HOWEVER. I find techs and most folk unable to install Windows correctly. Even I can't tell you how for this PC since I have yet to work with this motherboard and that drive setup. BUT NOT ALL IS LOST THERE. The motherboard maker must supply you how to not only setup the drives (settings, etc.) but which drivers to install and in what order to avoid CODE 10.
In parting I find a few PCs require us to disable Microsoft's Driver Update feature (how, what, etc is on the web) or they work on driver install and after a little time or a reboot fail. Then you reinstall the driver and it works again until the cycle repeats. Your motherboard maker may know if their board requires this tweak.
I built a custom gaming PC approximately 2 months ago (specs below). Everything had been working peachy this whole time. The setup I had uses two NVMe SSDs, the C: drive containing the OS and all programs, and the D: drive containing all documents, music, pictures, and downloads--as in, I had re-routed the default paths of those Windows shortcuts to the D: drive. Then one day, on Thursday 1/2/2020, all this happened...strap in:
1. In the middle of usage (as in, the computer had been running fine for hours), I tried to open some files on the D: drive, but Windows explorer crashed and stopped responding.
2. I told the computer to restart, since it had been a day or so since I had done so. Windows hangs up on the restart screen. After waiting about 5 minutes watching it just spin, I forcibly restarted using the power button.
3. Now the computer hangs on the motherboard screen on startup and won't boot to windows. A few attempts of restarting changes this to getting hung up on "preparing automatic repair".
4. I'm able to resolve the no-booting issue by disabling quick boot. PC boots as normal.
5. Upon a quick check in files, I suddenly see that the D: drive is not visible in Windows. It is also not visible in disk management. Just simply not there at all. However, upon restarting and checking BIOS, both drives are detected. Using shift+restart and clicking "use device" ALSO shows both drives.
6. Investigation into Device Manager shows that one of the two NVMe controllers has a Code 10 error and will not start. Drivers are up to date, checked and double checked. I try uninstalling the device and scan for hardware changes. Lo and behold, the drive appears in Windows. HOWEVER, I cannot open it or any files or folders linked to it, and attempting to causes windows explorer to hang and eventually crash. This error is reproduceable every time. Upon restart, the NVMe controller just goes back to the code 10 error.
7. Several other seemingly cascading errors crop up. My PIN code for logging in suddenly stops working, and I'm forced to log in with my MS account password. This seems to screw with many permissions on the PC, which resulted in (among other things) sound services refusing to start.
8. I do a system restore to a restore point 5 days previous to these issues. No changes. Even the PIN error persists.
At this point, after googling for ages, I take it to a local tech. He suggest a total wipe of the C: drive and a reinstall of windows. He does so--AND THE NVMe CODE 10 ERROR PERSISTS. We tried one other thing--my motherboard has 3 NMVe slots; M2M, M2P, and M2A. The D: drive (the one that has issues being detected) is in the M2A slot, and the working C: drive was in the M2P slot. We tried removing the D: drive and placing it in the M2A slot where the D: drive was previously. We then made sure to change the boot order in BIOS and tried to start. After POSTing, we got a black screen with a blinking cursor. No boot. The last thing I did was flash my BIOS. Despite successfully updating to a newer version, there were no changes to the issue. At this point, both the tech and I were unable to do anything further.
Of note is that the PC did not suffer any physical trauma of any kind. It was sitting under my desk, unmoved for 2 months. The case has excellent airflow, and I get rid of external dust fairly regularly.
Our current hypothesis: the M2A slot on the motherboard failed somehow, though for whatever reason, not completely.
Alternate hypothesis: the recent windows update broke the NVMe controllers. I have no idea how to even test this.
Things I am waiting to test: I have an NMVe drive USB reader ordered so I can at least test to see if the SSD itself is working.
Motherboard: Z390 Aorus Master (BIOS flashed to version F11c just today)
CPU: Intel Core i9-9900KF
GPU: Nvidia GeForce RTX 2080 Ti
RAM: 32 GB (4 x DDR4 G.Skill Ripjaws V series
SSDs: 2x Kingston 1 TB A2000 M.2 Nvme SSD PCIe
OS: Windows 10 64bit Pro, version 1909
If you need further info, please ask. I am baffled beyond belief by this issue.