FYI -
Here are the exact steps I used on many Windows 10 Pro x64 systems to correct this KB5034441 error.
Open CMD as Administrator:
Press Windows Key
Type in "CMD" (without the quotes)
Click on 'Run as administrator'
C:>reagentc /info
Windows Recovery Environment (Windows RE) and system reset configuration
Information:
Windows RE status: Enabled
Windows RE location: \?\GLOBALROOT\device\harddisk0\partition4\Recovery\WindowsRE
Boot Configuration Data (BCD) identifier: 35a5023d-a860-11ee-96cd-f84def5fa1af
Recovery image location:
Recovery image index: 0
Custom image location:
Custom image index: 0
REAGENTC.EXE: Operation Successful.
Note: partition 4 in WinRE.
C:>reagentc /disable
REAGENTC.EXE: Operation Successful.
C:>diskpart
DISKPART> list disk
DISKPART> select disk 0
DISKPART> list partition
Partition ### Type Size Offset
Partition 1 System 100 MB 1024 KB
Partition 2 Reserved 16 MB 101 MB
Partition 3 Primary 464 GB 117 MB
Partition 4 Recovery 1007 MB 464 GB
DISKPART> sel partition 3
DISKPART> shrink desired=250 minimum=250
DiskPart successfully shrunk the volume by: 250 MB
DISKPART> select partition 4
DISKPART> delete partition override
DISKPART> create partition primary id=de94bba4-06d1-4d40-a16a-bfd50179d6ac
DISKPART> gpt attributes =0x8000000000000001
DISKPART> format quick fs=ntfs label=”Windows RE tools”
DISKPART> list vol
DISKPART> exit
C:>reagentc /enable
REAGENTC.EXE: Operation Successful.
C:>reagentc /info
Windows Recovery Environment (Windows RE) and system reset configuration
Information:
Windows RE status: Enabled
Windows RE location: \?\GLOBALROOT\device\harddisk0\partition4\Recovery\WindowsRE
Boot Configuration Data (BCD) identifier: 35a5023f-a860-11ee-96cd-f84def5fa1af
Recovery image location:
Recovery image index: 0
Custom image location:
Custom image index: 0
REAGENTC.EXE: Operation Successful.
Restart Windows 10. Install KB5034441 through Windows Update without error.
Tried everything that everyone else suggested and nothing worked until I came across this. Thank you whoever you are and God bless you.