Windows update (KB5034441) Error (0x80070643)

Move Windows RE from there to the recovery partition by running

reagentc /disable

reagentc /enable

Thank you for this. Seem to recall this in the detailed instructions from MS, but then if the enlarged partition wasn't marked as a recovery partition, I guess reagentc /enable created the recovery image on C:

Having now followed your /disable /enable advice, I see the properly typed partition has 534MB of 1000MB used, 465MB free, so things seem to have worked. The size of 534MB also explains why an initial size of 500MB (or less) would result in a failure. So thank you 🙂 (the partition is still labelled and visible in Explorer, hence I can see the bytes consumed)

Turning now to my regular use laptop (so quite different machine ... as you seemed to have cured the other one 🙂), this is SSD, not rotating media, and I see warnings of disabling write caching before making any of these partition changes on SSD-based storage media. Correct?

Also, this machine has 3 recovery partitions!

Confirmed in DISKPART

That 12.6GB of recovery partition, and partitions 5 and 6 seem to provide way more space than required, yet KB5034441 continues to fail. This partition layout is as the machine came supplied from Dell.

Do I need delete partitions 4, 5 and 6, enlarge 3 ad add back a recovery partition of 1GB at the end of the disk? Any ideas on why 3??

Many thanks @Volume Z 🙂

Yes, you are right, the Winre.wim file can (and does) move when reagentc is either enabled or disabled. It seems like magic, but it is by design. Makes sense to move from the Windows OS system file location to the Recovery Partition location if there is some problem or corruption. This process can get interrupted with installing a new OS Drive (like a SSD) so the file is missing. That is when there is trouble. Some machines will need to have a complete ESD Recovery or borrow this special file from someone - search online you can also build this file. I believe this whole process is called the "Companion Operating System". Good luck.

When there is no recovery partition, the installation succeeds because Windows RE is enabled on a partition that is large enough aka drive C.

The strange thing is my older PC completed this troubled update without a Recovery Partition identified? I can't explain that.

I believe the explanation is that if there is no recovery partition, this 'whatever it is doing' element of the update is skipped hence no issue over partition size as that whole area of 'whatever is being done' simply doesn't run

I noticed the same thing. It is a mystery what the MS folks are doing with this Partition since it is essentially empty on Win 10 MBR, Win 10 GPT and Win 11 GPT PCs.

The partition is empty only after completing the MBR version of KB5028997. The partition is empty by default after running the disable command as Windows RE gets preserved on drive C. Every time the disable and enable commands are run, the recovery image changes its location. It fails to return to a partition that is not actually a recovery one and gets deployed on drive C instead.

The strange thing is my older PC completed this troubled update without a Recovery Partition identified?

With no recovery partition dedicated, the recovery partition is drive C which always has the necessary space available.