help fixing bcd or migrating data off of a cooked windows install

[cyan otter]

NOTE: INFORMATION HERE IS SLIGHTLY OUT OF DATE - I HAVE ADDED ONE MORE DRIVE AS EXTERNAL SSD TO BOOT INTO WINDOWS SO I CAN SHARE SCREENSHOTS - THIS CHANGES WHICH DRIVE LETTERS ARE BEING ASSIGNED. THIS IS JUST LEFT AS ORIGINAL POST OTHERWISE WITH ORIGINAL DRIVE LETTERS/
Trying to fix bcd. Im booting off of a flash win11 24h2, i mounted the FAT32 partition and assigned letter=Z
Cd Z/EFI/Microsoft/Boot
ren bcd bcd.bak
Bcdboot d:\windows /l en-us /s Z: /f UEFI

Then i exited the command prompt and exited the flash env and rebooted and got to the black screen that i hadnt seen in a while that says windows cant boot yada ya

i guess my D/Windows folder is cooked because its missing certain folders.. like WinSxS and others. No idea how that happened. (EDIT: I see the folder. not sure why i wrote this earlier. unless it was gone and then appeared when it tried to boot, probably i was just tired)

What are my current options. Tried to boot in safe mode but that failed too.

C drive is irrelevant here because that is a Windows 10 SSD.
D drive has Windows 11 and its windows crapped out early October during a BIOS update.. but was showing issues before that.
X drive is what my ventoy win11 gets mounted as
Z drive is the letter i assign to the FAT32 EFI partition that would be on the D

[cyan otter]

Still getting INACCESSIBLE BOOT DEVICE 🙁

[cyan otter]

List disk
Disk 0 - C drive
Disk 1 - d drive
Disk 2 - flash drive

List vol
..
Volume 4 - FAT32 - 100 MB - Hidden (should be SYSTEM?)
Select Vol 4
Assign letter=Z
Exit
Note that i used bcdedit not bcdboot.

bcdedit /enum ALL
Shows one identifier {bootmgr}
If i dont do assign letter=Z then it points to this

Windows Boot Manager
- - - - .

After i assign letter, it changes decice from parittion=\Device\HarddiskVolume1 to partition=Z

[bleak plinth]

@cyan otter Can you show list disk and list volume in diskpart?

[cyan otter]

yes. I plugged one more drive in so i can put a backup of F onto C - im close to saying f it and nuking the drive but i cant until i know for sure how to backup with dism and then get the files out from dism

previously i was running from the flash drive environment windows. I am now on an external SSD running Wind 10 so I cna use internet and screenshot here. note that as that is why drive letters have changed.
curently trying
https://learn.microsoft.com/en-us/windows-hardware/manufacture/desktop/dism-image-management-command-line-options-s14?view=windows-11
dism /capture-image /imagefile:"C:\CHRISTINE_BACKUP\install.wim" /capturedir:F:\ /name:"OSBackup" /compress:max /verify /EA
i see nothing happening but it will take a while since it hsa no progress indicator

attached one screenie from disk management. and one screenie from diskpart. The drive i am backing up is currently mounted as F instead of D as prior since i added an external ssd (C). List disk was a little tricky since Disk 1 and 2 are the same size but i was able to figure out the "correct" drive based on vol size.. That is, Disk 2 has my C drive, Disk 1 has my sister's F drive. G is just a useless backup partition i created. ignore D drive that's just a windows 11, ignore E that's just a 500GB SSD.

[cyan otter]

maybe usng compress max was a mistake but im not sure this is even running/// ill come back in an hour and check

[bleak plinth]

@cyan otter You have multiple drives with EFI partitions. So you need to do the right one

[cyan otter]

Yes. Alright dism is at least doing something this time, needed to come at it from a 25H2 WINRE environment rather than whatever i was in before.

Making an image of Sister’s drive partition (EDIT: HER DRIVE IS D:) - i confirmed it has her files. Putting an image of her par onto F:/ - which is my 1TB drive. Since I’m running off of winre (or winpe, idk whatever its called), needed to use a scratchdir that wasn’t my flash drive for logging. !command:

dism /Capture-Image /ImageFile:F:\THE_BACKUP\install.wim /scratchdir:F:\scratchdir /LogPath:F:\dismlog\dism.log /LogLevel:4 /CaptureDir:D:\ /name:”OSBackup” /compress:max /verify /EA

if i really need to read it, Microsoft has a paper in rtf format on how dism works, or its image format, or something. i didnt read it obv. Probably should at some point.

I’ll come back in an hour, dism is definitely running this time

[cyan otter]

Dism finished. Am still in the flash drive environnent.

Tried to load hive SOFTWARE from the bad OS. It doesn’t 😄

reg load HKLM\TempHive2 D:\Windows\System32\Config\SOFTWARE ERROR: The configuration registry database is corrupt.

[cyan otter]

https://learn.microsoft.com/en-us/troubleshoot/windows-client/installing-updates-features-roles/system-registry-no-backed-up-regback-folder
REGBACK IS TURNED OFF BY DEFAULT - THAT'S GOOD TO KNOW. WHYYYYYY
so this reg hive is a goner. no software reg hibve i believe means you can't do a repair with dism. So now its tme for manual file recovery or whatever

[cyan otter]

going to try using regripper but need to wait for kali linux to download. I will continue this tomorrow as it is getting very late here. https://www.tspi.at/2021/04/04/mswindows10recoverdamagedhivefile.html#gsc.tab=0

[spiral mural]

you are trying to fix BCD... you didnt explain..why you were doing that in the first place...or how you ended up in that situation...
also it seems like you have messed up..even more while trying to fix it..

first tell whether you did something or something happened..before you get this BSOD... "inaccessible boot device"...

[cyan otter]

Initial State (early Oct/late Sep): Windows begins turning off randomly when PC is left idle (e.g. not under heavy load).
In early October, ran a BIOS update using the gigabyte motherboard utility that runs from within Windows => Windows would not boot. (Which is why everyone recommends using a flash drive for BIOS updates). BIOS update succeeded at the time and i could get into BIOS - but it was just a black screen if you tried to run the Windows OS.

I assumed the EFI was possibly corrupted. Wanted to rebuild that. It completes.. doesn't say any error occurred.
chkdsk /f found no errors.

attempting to boot into the bad Windows OS will give "inaccessible boot device". https://learn.microsoft.com/en-us/troubleshoot/windows-client/performance/stop-error-7b-or-inaccessible-boot-device-troubleshooting
BIOS sees the windows boot manager for the bad drive. bootrec /scanos fails to find windows in the bad drive.
I haven't tried running dism repair yet..

I am currently at this stage, where startup repair fails, i begin to suspect issue may be in a registry hive - SOFTWARE turns out to be corrupted. did I break it?hell if i know. Let's assume yes. Not sure which of the above commands could have broken it.

SOFTWARE reghive has last modified date = OCT 4, 2025, i don't know enough about NTFS to answer what happens if faulty OS modifies it.

For backups: There were no backups setup on my sister's PC at the time. Any backups here are after the fact. I used dism to make an image of the primary partition, used macrium reflect to make one proprietary image. Am going to try dism online and see if that can repair a copy of the first image.

[spiral mural]

Wish you had contacted here.. before the bios update!..
Welp!...it cant be helped...

Did you try cmos reset when you first had the black screen?.