Windows update (KB5034441) Error (0x80070643)

Read through the 32 pages of suggested actions on this post. There are a number of things you need to do. I advise doing the things you are comfortable with first, the simplest first, and those from the last pages last.

First from CMD line reagentc /info

Reagentc needs to be working and enabled

You might try to put the needed Recovery files in the folder noted on your main OS drive partition.

Windows > System32 > Recovery

$PBR_ResetConfig.xml

Reagent.xml

Winre.wim

(I made sure all these files came from a working Win 10 machine with the same version of Windows on another machine, this may make a difference)

Then point the reagentc to your OS partition with disable /enable (from CMD pointed to Windows > System32 > Recovery)

Then reagentc /disable

Then reagentc /enable

restart pc

CMD line Admin - reagentc /info See where the reagent recovery is pointed.

Try the update now.

Does it make sense to have your recovery files located inside the Win 10 System File Folders? Not really. However it seems to work. I also upgraded from Win 8.1 HP Laptop to Win 10. I think another solution may be a clean Win 10 install from a EDS Thumb Drive. This is a last ditch effort action.

Good luck.

To recap -

1. I'm working with the assumption that the issue is that the RE partition is too small - according to MS.
2. I'm able to do the diskpart/cmd but I wanted to see if people who are uncomfortable with doing them (i.e., they don't have a full system to bare metal backup process in place) could do something easier.
3. I used a partition tool (and several free ones are listed in this thread) that can shrink the main C partition so you can expand the WIN_RE partition. I increased mine using this method.
4. When it still had errors, and after increasing it again with no effect, I opened a "Run as Administrator" Command Prompt and entered reagentc.exe/enable - rebooted and it worked.

IMHO the issue is MS either isn't interested in giving the general users a command prompt file that auto-resizes the C and WIN_RE partitions.

NOR are they interested in giving everyone the straightforward process that worked for me which would mean they would have to recommend a partition management tool.

My case is funny. My system (HP laptop) was upgraded from 8.1.

DISKPART> list part 

  Partition ###  Type              Size     Offset 

  -------------  ----------------  -------  ------- 

  Partition 1    Recovery          400 MB   1024 KB 

  Partition 2    System            260 MB   401 MB 

  Partition 3    Reserved          128 MB   661 MB 

  Partition 4    Primary           908 GB   789 MB 

  Partition 5    Recovery          2048 MB  909 GB 

  Partition 6    Primary           20 GB    911 GB  

DISKPART>
DISKPART> list vol

  Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
  Volume 0     E                       DVD-ROM         0 B  No Media
  Volume 1     C                NTFS   Partition    908 GB  Healthy    Boot
  Volume 2         RECOVERY     NTFS   Partition     20 GB  Healthy
  Volume 3                      NTFS   Partition    400 MB  Healthy    Hidden
  Volume 4                      FAT32  Partition    260 MB  Healthy    System
* Volume 5         WINRE        NTFS   Partition   2048 MB  Healthy    Hidden
DISKPART>

Because recovery partition is located even prior of system the Upgrade created a new one for W10 but somehow failed there.

I found no winre.wim on the partition 5, only the old 8.1 one on partition 1.

I extracted W10 winre.wim from distribution .iso and copied it to recovery\windowsre on partition 5 manually. Below are old and new winre.wim -s to compare.

04.12.2023  03:30       474 223 495 winre.wim 

08.11.2012  12:59       213 949 909 winre.wim.old

I resized partition 5 to 2GB as you can see above. RE is enabled.

Windows RE status:         Enabled

Windows RE location:       \\?\GLOBALROOT\device\harddisk0\partition5\Recovery\WindowsRE
Boot Configuration Data (BCD) identifier: df43008f-078f-11ed-bf0a-e4313577db01
Recovery image location:
Recovery image index:      0
Custom image location:
Custom image index:        0

But the update repeatedly fails. Obvious guess is that to be successfully installed it does need the very first recovery partition 1 to be large enough, not the configured and set as active RE partition 5. And this scenario is something related not only to me but many other users with recovery partitions located prior system/boot one. diskpart can not resize it and creates a new one, which is not getting identified by update process as it tries to use only first one and why it fails.

Worth to mention I found and deleted obsolete recovery boot entry in BCD store, it did not help to solve the update issue.

Did this, worked, and now I can eventually jump out of this nightmare.

You go to https://www.microsoft.com/en-us/software-download/windows10

Create Windows 10 installation Media

Download Now

I DID NOT DO A CLEAN INSTALL . I opted to keep my files.