[SOLVED] Dell Optiplex won't boot into Windows 10; don't know local Admin pass

dbdan22 · Nov 15, 2023

Hi,

So I have a situation with a Dell Optiplex that won't boot into Windows 10 64 bit.

One of 3 things happens depending on sunspots or the phases of the moon:

It shows the Dell logo and then goes into the circling dots, endlessly (my user left it on overnight and it stayed circling), or...
It starts the Automatic Repair which of course does not work, or...
It blue screens with WINLOGON_FATAL_ERROR (c000021a)

Further complicating this sorry state of affairs is that I do not know the local admin pass. This PC was set up by someone who is no longer here. I know the domain admin pass, but not the local admin pass.

Why is this a problem? Because when you boot into recovery mode off the hard drive, which it will do, it then asks for the local admin pass before letting you do anything. And I don't know it!

What I can do is boot off a USB drive I prepared with Rufus, but that somewhat limits what I can do against the installed version of Windows. It's now an offline image.

I've done what I could:

I was able to do a sfc /scannow with the /OFF... switches, it found issues and fixed them.
Likewise I was able to do a Dism /Image:C: /Cleanup-Image /RevertPendingActions
I was able to snag a memory.dmp to the flash drive

Of course this made no difference, still won't boot into Windows. Keeps on with automatic repair, circling dots or BSOD.

Let me return to the Admin password issue if I may. I'm aware of the hack with utilman. But that only works if the system boots into Windows. This won't.

So if some kind soul would educate me on how to:

change the admin pass on what is essentially an offline image so I can boot to recovery from the hard drive and work on the online image, and
then proceed to troubleshoot the other problems I'm having

... I would be greatly indebted.

Please let me know what info you need to troubleshoot this.

Thanks,
Dan

xrobwx71 · Nov 15, 2023

Unfortunately, under Sysnative Rules, we cannot help you get around the Admin password.

Code:

2.This includes information about or links to any site that contains information intended to violate the Terms of Service or End User License Agreement of any service, product, or application as well as requesting or providing information on hacks or cracks.

Sysnative Rules

The few bits of advice I can give you:

Use the USB you made with Rufus and clean install Windows. If you can access the files on the disk try to backup before doing anything.

Also, if its a Microsoft Account, not a local account,you can logon to the MS Account and change the password there.

See here as well. Redirecting

Since the website link I provided is a MS site and my advice above does not violate any MS TOS or EULA, I feel it's fair to share those.

dbdan22 · Nov 15, 2023

Understood.

Can we troubleshoot the WINLOGON_FATAL_ERROR (c000021a) error, and how that can be fixed from a recovery USB? I was able to get a crash dump. What else might you need to troubleshoot this?

Thanks.

I might add that the NvRAM passed Dell Diagnostics and a CHKDSK so I doubt it is hardware.

Also a check of system restore showed no prior restore points, but that may have been because it was looking at the currently mounted image which is of course the USB stick. How do you do a system restore of an offline image?

dbdan22 · Nov 15, 2023

So there's an article here that says to fix the c000021a BSOD, run BCDEDIT and turn off integrity checks - bcdedit.exe /set nointegritychecks

But again, I'm running from the USB stick, not the main Windows image which is offline.

BCDEDIT has a switch /store
bcdedit /store <filename>

<filename> Specifies the file name of the boot configuration data store.
If the file name contains spaces, it must be enclosed in
quotation marks ("").

But how do I refer to the BCD store of the offline image?

Thanks.

LMGTFY:

Ummmmmm...... Top 4 Solutions to Repair Windows 10 BCD Errors Easily ?

LOL.

xrobwx71 · Nov 16, 2023

I'll ask one of our trained experts for help. Thanks for understanding.

@ubuysa

ubuysa · Nov 16, 2023

Hello, I'll help as much as I'm able, with the understanding that I can't help you circumvent the unknown admin password issue, but I may be able to help identify why it's BSODing.

The first thing I'd want to know is what happened to make it stop booting? You just say that "it won't boot" but it would be useful to know what happened prior to this problem occurring. If something was working and now it's not, then something has changed. What changed? That may be a big clue.

Please disconnect all external devices except for the mouse, keyboard, and one monitor. Then see whether it will boot?

You mentioned that you have a dump file from the PC? Please upload it to a cloud service with a link to it here. Please ensure that we don't need to login to download the dump (ie. make it public).

The 0C000021A exception code you get with the BSOD is a SYSTEM_PROCESS_TERMINATED, which suggests of course that one of the critical Windows processes terminated during the boot process. The most likely cause of that happening is going to be a hardware problem and bad RAM is one of the common hardware problems.

On another PC download Memtest86 (free), use the imageUSB.exe tool extracted from the download to make a bootable USB drive containing Memtest86. Then boot that USB drive, Memtest86 will start running as soon as it boots. If no errors have been found after the four iterations of the 13 tests that the free version does, then restart Memtest86 and do another four iterations. Even a single bit error is a failure.

If you have a Windows installation system on a USB drive, does it boot that OK? Is it stable running that OS? Can you navigate via command prompt to all drives and all partitions? You might do better using a USB drive made with the Windows Media Creation Tool rather than an ISO burned via Rufus.

DKenn · Nov 16, 2023

You system should have attempted a Startup Repair during this process. Can you access the log file - C:\WINDOWS\System32\Logfiles\Srt\SrtTrail.txt

This should tell us why it failed to repair your system. If the Startup Repair was not run for some reason, I would suggest trying it.

dbdan22 · Nov 16, 2023

Hi,

Thank you ubuysa and DKenn for your replies.

What happened to make it stop booting? I don't know. This user doesn't shut her PC down despite being asked many times. She came in one day and it wouldn't boot into windows. That's all I know. If I were a betting man I'd say it crashed, lost power or rebooted unexpectedly during Windows updates.

memtest is probably not necessary, I've already run full dell diagnostics, it passed. chkdsk also shows no issues (crucial nvram)

yes it boots ok from a recovery disk and is stable.

memory.dmp and srttrail are uploading now ...
21A <- folder

Thanks again

ubuysa · Nov 16, 2023

Please run Memtest86 twice. It is necessary.

dbdan22 · Nov 16, 2023

Running.....

DKenn · Nov 16, 2023

Root cause found:
---------------------------
Bugcheck c000021a. Parameters = 0xffffe301df0586d0, 0xffffffffc0000428, 0x0, 0x29eaaa50000.
Boot critical file is corrupt.

Repair action: File repair
Result: Failed. Error code = 0x57
Time taken = 1437 ms

Repair action: System files integrity check and repair
Result: Failed. Error code = 0x57
Time taken = 1000 ms

According to the SrtTrail.txt your fault lays with a corrupt boot file. It might be worth repeating the offline SFC /SCANNOW to create a log file, for example:

sfc /scannow /offbootdir=c:\ /offwindir=c:\windows /offlogfile=c:\sfc_log.txt

dbdan22 · Nov 16, 2023

Memtest 2 passes, 0 errors.

sfc reported no integrity violations

sfc_log.txt uploaded to the folder OneDrive

JSntgRvr · Nov 16, 2023

Try to boot in Safe Mode. Run this command:

bcdedit /set {default} safeboot network

If successful, restart the computer.

jcgriff2 · Nov 16, 2023

More often than not, a 0xc000021a error = HDD/SSD error.

The internal drive is likely shot.

If you have an SSD, go to manufacturer's support site and check for a firmware update.

Regards. . .

jcgriff2

dbdan22 · Nov 16, 2023

Thank you for your replies.

JSntgRvr: Ran bcdedit, says it completed, but still bluescreens with 21A

I uploaded another dump: memory3.dmp into the same folder as above.

jcgriff2: the drive, a Crucial P2 512 SSD, passes both Dell full diagnostics and a CHKDSK. There was a firmware update last year, which was applied with Crucial Storage Exec, but none since. I checked the PC next door to this one, part of the same order and also updated with the same Crucial. No updates.

- d.

dbdan22 · Nov 17, 2023

DKenn: y'know what I didn't do is a dism /cleanup-image /restorehealth against the image. maybe I should try that and post the log and anther SrtTrail.txt (note to self). I'll be onsite later this morning.

ubuysa · Nov 17, 2023

Thank you for running Memtest86. With problems like this you can never assume and it's always wise to check the obvious things first.

I have all three kernel dumps and they are all identical, so the boot failure is consistent. The bugcheck in each dump is a WINLOGON_FATAL_ERROR (as you know), which means that a critical Windows subsystem failed during the boot process. Argument 2 of the bugcheck contains an exception code of 0xC0000428 which indicates an INVALID_IMAGE_HASH. That means that a corrupted image was loaded - which gells with what @JSntgRvr was finding with SrtTrail.txt.

Not shutting the PC down isn't a problem, I never shut mine down, it's on 24x7. Your thought that it could have been a power failure is a distinct possibility, I run mine via a UPS (because the power here in Greece isn't always reliable). Other possibilities are a glitch during a recent restore from a backup - is that likely? - or a recent driver update/install - is that likely?.

Was the PC taking automatic restore points by any chance? You can restore to an existing restore point from the Windows installation media.

I think attempting a DISM .... /restorehealth against the image is a sensible idea - you have little to lose at this point.

BTW. If there is any important data on any drives in that PC I would sugest you remove the drives and back them up on another PC at this point. Just in case.

This isn't a bugcheck I've ever come across before and I know of no silver bullet that can fix the image corruption, so I'm going to flag two of the BSOD gurus on here; @x BlueRobot and @axe0 to see whether they can be of more help.

I'll keep watching this thread of course.

JSntgRvr · Nov 17, 2023

Lets take a look at the system.

Please download Farbar Recovery Scan Tool and save it to a flash drive.

Note: You need to run the version compatible with your system. If you are not sure which version applies to your system download both of them and try to run them. Only one of them will run on your system, that will be the right version.

Boot in the Recovery Environment Command prompt

Once in the command prompt

In the command prompt, type notepad and press on Enter
Notepad will open. Click on the File menu and select Open
Click on Computer/This PC, find the letter for your USB Flash Drive, then close the window and Notepad
In the command prompt, type e:\frst.exe (for the x64 version, type e:\frst64.exe and press on Enter
Note: Replace the letter e with the drive letter of your USB Flash Drive
FRST will open
Click on Yes to accept the disclaimer
CPut a check mark on List BCD
Click on the Scan button and wait for it to complete
A log called frst.txt will be saved on your USB Flash Drive. Attach it in your next reply

dbdan22 · Nov 17, 2023

Hi,

I was able to run dism /cleanup-image /restore health on the installed (offline) image from the recovery flash drive.

It ran successfully but did not help, still BSOD with 0xc0000021a

I created a new folder POST DISM OneDrive

In it you will find the DISM log, the startup recovery log post dism, and the memory dump from the reboot immediately following the dism

JSntgRvr, I didn't see your post until just now, I'll get right on it.

Thanks to all.

dbdan22 · Nov 17, 2023

ubuysa a battery backup makes all the difference in the world. without one, we ask our users to shut down at the end of the day. recent restore from a backup? nope. driver install? Possible. I wish Windows would leave the driver updates to Dell Command Update. I keep forgetting that setting to keep Windows Update out of it.

[SOLVED] Dell Optiplex won't boot into Windows 10; don't know local Admin pass

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