Windows Insider BSOD 0cx000021a

ch3mn3y said:

What I want to try is installing the 18850 using USB drive without removing user data.
Is it OK? Or maybe I should try something else?

Can't do that unless you get it to boot. The best you can do is a parallel install.

I suspect you have a corrupted file system. Create the 18850 USB drive using UUP dump to get the ISO(make sure you get the amdx64 version). Boot it, press Shift+F10 at the first install window, find your boot drive (may or may not be C:) then run chkdsk x: /f (replace x: with the drive letter for your boot drive). See if that fixes the problem.

If not then use the same USB flash drive to do a parallel (Custom) install as follows:

How to Custom Install Windows 10

Following the directions will leave your current installation in Windows.old and your new install off of C:\. All your data will be there but you will have to reinstall any programs that do not come with Windows 10.

Just make sure you selected the right one to download. Looks like it should be this one:

Windows 10 Insider Preview 18850.1000 (rs_prerelease) amd64

x64

cf92df2c-210f-44c7-85e3-bae94249a763

ch3mn3y said:

It seems that my Windows have some other problem...

Now I'm not only with 0xc000021a, but with 0xc0000221, 0xc0000185 & 0xc0000098 as well... Got them all when trying to boot from USB...

Ehh. Trying with freshly downloaded iso from UUP.

you should be able to boot into recovery and select windows system restore. is there any such option?

as for your error codes -

0xc000021a - an error has occurred in a crucial user-mode subsystem.

From Microsoft -

Microsoft said:

Cause


This error occurs when a user-mode subsystem, such as WinLogon or the Client
Server Run-Time Subsystem (CSRSS), has been fatally compromised and security can
no longer be guaranteed. In response, the operating system switches to kernel
mode. Microsoft Windows cannot run without WinLogon or CSRSS. Therefore, this is
one of the few cases where the failure of a user-mode service can shut down the
system.

Mismatched system files can also cause this error. This can occur if you have
restored your hard disk from a backup. Some backup programs might skip restoring
system files that they determine are in use.

Resolution


Running the kernel debugger is not useful in this situation because the
actual error occurred in a user-mode process.
Resolving an error in a user-mode device driver, system service, or
third-party application: Because bug check 0xC000021A occurs in a
user-mode process, the most common culprits are third-party applications. If the
error occurred after the installation of a new or updated device driver, system
service, or third-party application, the new software should be removed or
disabled. Contact the manufacturer of the software about a possible update.

If the error occurs during system startup, restart your computer, and press
F8 at the character-based menu that displays the operating system choices. At
the resulting Windows Advanced Options menu, choose the Last Known
Good Configuration option. This option is most effective when only one
driver or service is added at a time. If this does not resolve the error, try
manually removing the offending software. If the system partition is formatted
with file allocation table (FAT), use an MS-DOS startup disk to gain access to
the computer's hard disk. If the system partition is formatted with NTFS file
system, you might be able to use Safe Mode to rename or delete the faulty
software. If the faulty software is used as part of the system startup process
in Safe Mode, you need to start the computer using the Recovery Console in order
to access the file. If a newly installed piece if hardware is suspected, remove
it to see if this resolves the issue.

Try running the Emergency Recovery Disk (ERD) and allow the system to repair
any errors that it detects.

Resolving a mismatched system file problem: If you have recently
restored your hard disk from a backup, check if there is an updated version of
the Backup/Restore program available from the manufacturer. Make sure the latest
Windows Service Pack is installed.

Microsoft said:

Resolution

Running the kernel debugger is not useful in this situation because the actual error occurred in a user-mode process.
Resolving an error in a user-mode device driver, system service, or third-party application: Because bug check 0xC000021A occurs in a user-mode process, the most common culprits are third-party applications. If the error occurred after the installation of a new or updated device driver, system service, or third-party application, the new software should be removed or disabled. Contact the manufacturer of the software about a possible update.
If the error occurs during system startup, restart your computer, and press F8 at the character-based menu that displays the operating system choices. At the resulting Windows Advanced Options menu, choose the Last Known Good Configuration option. This option is most effective when only one driver or service is added at a time. If this does not resolve the error, try manually removing the offending software. If the system partition is formatted with file allocation table (FAT), use an MS-DOS startup disk to gain access to the computer's hard disk. If the system partition is formatted with NTFS file system, you might be able to use Safe Mode to rename or delete the faulty software. If the faulty software is used as part of the system startup process in Safe Mode, you need to start the computer using the Recovery Console in order to access the file. If a newly installed piece if hardware is suspected, remove it to see if this resolves the issue.
Try running the Emergency Recovery Disk (ERD) and allow the system to repair any errors that it detects.
Resolving a mismatched system file problem: If you have recently restored your hard disk from a backup, check if there is an updated version of the Backup/Restore program available from the manufacturer. Make sure the latest Windows Service Pack is installed.

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the other 2 codes you mentioned -

0xc0000185 = The boot configuration data for your PC is missing or contains errors

0xc0000098 = Boot Configuration Data corrupted

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Don't know if this will help or not, but it is from Microsoft - https://support.microsoft.com/en-us/...startup-issues