Windows 10 0xc00021a boot error, i had tried almost everything... Its possible to repair Win10 without losing system settings?

[ruthan]

Hi,
im struggling for quite a long time with 0xc00021a Windows 10 boot error, its UEFI version of WIndows 10, if it matters and i have only EFI partition and one 1 machines not Recovery partition and not ESR 128 Mb service partition, i never needed it for anything and when i upgraded install it was not create, its probably not mandatory same as Recovery partition, because recovery enviroment is in C:\Recovery hidden folder too.

I have tried a lot of things, sfc - is fine, dism is fine. Error description is for lots of source of this error.. I have tried to enable ntbtlog.txt, but it seems that its happening before log is create, so i dont have any clues to fix it.
It seems to new bug.
  It happened after some update, i might get out of space during updating, because of app generated 30 GB error file.  I had some restore points, but during restoring i got error, maybe because of now enough space and after restore point data disappered and my last full backup is quite old.

  I have tried manaul BCDedit fixing, all boot fixing utilities which i found - Paragon, EasyUS, Aomie, Dual boot repait, VisualBCD, Bootice, Lazesoft. Bootsec, Hasleo Easy UEFI, including deleting and rebuild EFI partition.
  I haved tried all boot modes - enable logging, safe mode, recovery, autorepair - there is error hardisk not found..

   What is more interesting, i even managed to replicate error on Windows 10 togo on USB-NVME driver, on different hardware.. (intel Z370 + AMD 450 - Ryzen 2600 )Its probably again cause by some recent update, or by some BCD change, because some tools are updating try to fix, all connected BCD by mistake... and im unable to fix it even on USB-NVME install on other computer.

  Hardware is ok for sure, because its happening on multiple devices, liveCD are booting fine. Im quite sure that is not because some virus.

  Only thing which im able to ""fix" it is restore whole NVME-USB installation EFI + System partition, restore EFI partition alone is not enough its somehow connected.
  I googled alot, but found only generic tutorials for classic - sfc/dism / bcd fixing.. Disabling some addional disk or disconning devices is not helping too.  I did not found success stories, just people who git complete reinstall or machine reset.

Its possible somehow repair WIndows 10 without losing system settings - installed programs, registry settings and normal files?
I saw some /auto setup.exe settings, but when i tried setup.exe /auto othre commands, i always get unknow option /auto error.

 

Edited 12 hours ago by ruthan

[ruthan]

I was experimenting with NVME-USB install, this time and recovered only main windows partition and used EFI partition adjusted by lots of experimenting and this time it booted fine. Right before partition recovery i tried to boot, so did nothing new with EFI partition to make system bootable.

  I can also say that its crashing before graphical BCD metro menu with multiple enteries its loaded, its loading for while, its not quick crash, like 10 second.. I have multiple BCD enteries because of my experiments.
  

  Im not aware that i did something extra with WIndows install on main parition its stuck to 1803 version, because USB version upgrading problem, some security roll up updates where installed, also constant upgrading update which is failing its running.. and i installed a few "normal" problems to make it more usable, nothing suspicious, i also doubt that i have some virus and same one on my 2 machine. It has to be something ugly.

   Only thing which i read online about this error is that it could be related to winlogon.exe and csrss.exe but when DISM and SFC run fine, they should be fine.
   
   If someone know how Windows 10 UEFI boot sequence is working step by step, it may be helpful. 

   I have bad memory but i maybe tried to set number of processors through msconfig to make boot a bit faster before it broke, i saw it some video.. but because i recreated EFI partition if its some parameter there it should be gone, unless its something saved in registry or other system file.
   But i have tried the same thing with NVME-USB and its still booting, so its probably not it.. im not sure if WIndows boot its by default multithreaded. 
   When i removed bcd experiments to avoid BCD menu, whole boot is now like 15 second vs 10 second crash before, it be in more advanced phase of booting, but even when bootlog is force for every boot entry and i use textstyle bootmenu instead of metro one, its still crashing the same way.

Edited 5 hours ago by ruthan