[SOLVED] Inaccessible Boot Device BSOD after not doing anything unusual nor installing new HW

[mrbohnke]

We were yesterday just watching some movie, turned the computer off when it ended, tried to turn it on several hours later, got this BSOD.

We've got no real suspicion of a culprit, since we didn't install any new hardware and were not doing anything out of the usual. The only thing I can think of is a Windows 10 update the computer got one or two hours before. I have no real details on the update since it happened on the background, but I think I remember it was Intel related —maybe for the integrated graphics or network card? I already tried to disable the integrated graphics (since I use a dedicated card) without success. I also got a repair disk and looked for my partitions with diskpart > list vol, apparently they're all right there.

 

[Colif]

what did list vol look like? the partition labels will give me an idea of what format hdd is in.

is PC custom or brand name? If custom, what motherboard is it? If brand name, what make/model?

its possible we just need to swap the boot method but I need to know what format drive is and motherboard model before i can go guessing.

 

[mrbohnke]

Both HDDs are NTFS. The PC is custom made, the motherboard is a GA-Z170M-D3H from Gigabyte.
Transcription from list vol:
https://i.imgur.com/CL1aYvp.png

Thank you very much.

 

[mrbohnke]

FYI, already tried:
BOOTREC /FIXMBR <-- Says ok
BOOTREC /FIXBOOT <-- Access denied
BOOTREC /REBUILDBCD <-- Found the Installation but Element not Found on Yes

 

[Colif]

often I have found the best answer to this error is a fresh install. https://www.lifewire.com/how-to-rebuild-the-bcd-in-windows-2624508 might help (same commands as you tried but with more help)

Your drive appears to be in MBR format so I wonder whats showing as boot drive in the bios features tab of the BIOS (see page 30 of your manual) as if it shows UEFI drive as boot, its not going to work for your PC.

Is drive D on the ssd? As if its on the 1tb hdd, i can see why the PC isn't booting - https://www.linkedin.com/pulse/what-system-reserved-partition-windows-1087-abdul-salam/ - the system reserved partition is meant to be 1st partition of the drive as it contains the boot files and a PC set up to boot using MBR has to have it as 1st partition on the drive.

Now why is the System reserved partition showing with a drive letter?
Did you have ssd in PC when you installed Win 10? Is D drive on the ssd?

 

[mrbohnke]

Hi! The drives are MBR, the system is installed in the SSD.The thing is, I can't understand why the System Reserved has a letter, it showed like that when I first started the DISKPART but it used to be unassigned as usual. I also can't understand why the letters of the volumes are all scrambled up. What here shows as C: (formerly X: ), is the HDD storage drive (movies and stuff). D: and F: (formerly C: ) are in the SSD, being the latter the one that appears as boot drive in the BIOS (not shown as UEFI, alright).

Since I couln't get anything done, I started to try stuff like unassigning the D from the System Reserved volume, or changing letters to the way they used to be (both from Diskpart and from a live dist partition tool), but everything goes back to the way it shows in the image. ¿?

I'm almost totally convinced now that the only solution will be a fresh install, but I also would like to understand what the heck did happen to get to this.

 

[mrbohnke]

Hello again,
I finally got to start the system. Now I'm trying to find out what went wrong and why but, for now I'm celebrating and considering myself lucky after two days of hellish neverending trial and error. I'm going to describe what I did to finally get the system to start, I assure you all this has been a complete mystery to solve, despite the steps now sounding pretty obvious. Note: if you are reading this looking for answers for your own problem, remember to carefully read the whole thread. Also remember my drives are MBR.

After trying to repair the installation using several Windows Recovery Disks (Startup Repair) with ZERO success (it always said Windows couldn't repair a thing), and trying all the possible combinations and variations of the startup recovery commands holy trinity (BOOTREC /FIXMBR + BOOTREC /FIXBOOT + BOOTREC /REBUILDBCD) receiving error after error (even different errors between tries !?), my last message here got me thinking about drive letters, boot order and the mysteriously lettered System Reserved partition ("boot partition" hereinafter) @Colif mentioned. I gathered some courage for a last try, downloaded something I had heard of some time ago called Windows PESE (some sort of Live installation of Windows stuffed with handy tools) and burned it into a bootable USB drive (not without some problems, because laptop with macOS). I disconnected my storage drive of happiness since I didn't want to have any accident (you KNOW this could happen) with my movies-games-stuff, got the USB to work and made backup of everything else important from the system drive using patience and another USB drive. Then, here come the key steps:

- Opened the Computer Management tool (compmgmt.msc).
- Formatted the Boot Partition.
- Reassigned volume letters so it looked like before the "problem" (C: for the system drive, but also Z: for the Boot Partition volume, so we're able to work with it in the meantime).
- Opened an elevated Command Prompt (cmd.exe).
- Typed: bootsect /nt60 Z: /force /mbr (to write boot records to the boot partition and MBR).
- Typed: bcdboot c:\windows /s Z: /f ALL (to recreate the boot configuration data on the Boot Partition).
- Back in the Computer Management tool, removed Boot Partition's letter (and left it unassigned).
- Turned off the machine.
- Removed the USB (this is important, believe me).
- Started the computer with eyes closed, clenched teeth, bated breath.
- Be suddenly filled with joy.

As I said at the beginning, now I want to understand what, how and why went wrong in the first place, and will update this thread if I have some new info but, for now, thank you, good night and good luck!

 

[Colif]

Have a look in windows update - update history and see what update you got

I can only guess that the hdd are connected to the motherboard in such a way that what was drive Z is in slot 1 of the board and your normal C drive is in slot 2, In theory this shouldn't have any effect on how the PC boots. MAkes me curious what update you got earlier as I don't know why the drive letters got mixed up.

I marked your answer as Best as you solved it yourself. At least the how to fix part, not the why did it happen part