Fix Windows Update Error 0x80070643 (WinRE)

If Windows Update keeps choking on the same security update and throwing error 0x80070643, you are almost certainly looking at the WinRE recovery partition problem. The update that triggers it (KB5034441 and its relatives) ships a new Windows Recovery Environment image to patch a BitLocker bypass, but the recovery partition Windows created during setup is too small to hold the larger image. The download succeeds, the install fails, and the update retries on every reboot.

The good news: this is a layout problem, not a corruption problem. You do not need to reinstall Windows. You need to shrink your main partition by a few hundred megabytes, hand that space to the recovery partition, and let the update finish.

Key takeaways

• 0x80070643 on the recovery update means the WinRE partition needs at least 250 MB of free space, which most factory layouts do not have.
• The fix is to disable WinRE, shrink the OS partition, extend or recreate the recovery partition, then re-enable WinRE.
• If your PC has no recovery partition at all, Microsoft says you can safely ignore this update and hide it.
• A simpler resize is available through a partition tool, but the command-line method below is free and reliable.

Pick the right path for your situation

Not every machine that shows 0x80070643 needs the partition surgery. Use this table to figure out which path applies to you before running any command:

What reagentc /info shows	What is happening	What to do
Enabled, with a small Recovery partition	Partition too small for new image	Resize WinRE (steps below)
Enabled, no recovery partition listed	Update does not apply to you	Hide the update, ignore
Disabled, no partition	Same, not exposed	Hide the update
Error on a non-recovery update	Component store corruption	Reset Update components (see FAQ)

The whole point is to avoid touching partitions unless you actually have the small-WinRE layout. Confirm first, then act.

Confirm the cause before you touch partitions

Open an elevated Command Prompt (press Start, type cmd, choose Run as administrator) and run:

reagentc /info

Look at the Windows RE status. If it says Enabled and lists a Recovery partition, you have the layout that triggers the error. Note the partition's hard disk and partition number. Then check the recovery partition's size in Disk Management (right-click Start, choose Disk Management). If it is around 500 MB with little free space, the resize below applies.

Resize the WinRE partition

This is the official Microsoft procedure. Take your time and read each diskpart command before pressing Enter, because selecting the wrong partition can damage data.

1. In the elevated Command Prompt, disable the recovery environment so the partition can be modified: reagentc /disable

2. Start the partition tool: diskpart

3. List disks and select the one holding Windows (usually disk 0): list disk then select disk 0

4. List partitions and select the OS partition (the large one, type Primary): list partition then select partition 3 (use your actual number)

5. Shrink it by 250 MB to free space for recovery: shrink desired=250 minimum=250

6. Select the recovery partition (type Recovery): select partition 4 (use your actual number), then delete it: delete partition override

7. Recreate it with the right type. For a GPT disk run: create partition primary id=de94bba4-06d1-4d40-a16a-bfd50179d6ac then gpt attributes=0x8000000000000001. For an MBR disk use: create partition primary id=27

8. Format it: format quick fs=ntfs label="Windows RE tools" then exit with exit

9. Re-enable the recovery environment so the new image installs into the resized partition: reagentc /enable

10. Confirm it is healthy: reagentc /info, Windows RE status should read Enabled. Now rerun Windows Update.

After re-enabling WinRE, go to Settings > Windows Update and click Check for updates. The previously failing update should now install. This same disk-space discipline is worth keeping in mind for other update failures, see our guide on the 0x800f0922 EFI partition update error, which is also a space problem, just on a different partition.

When resizing is not the answer

If reagentc /info reports that WinRE has no recovery partition or is Disabled with no partition listed, you do not need this update. Microsoft has confirmed there is no automatic fix coming, and a machine without a recovery partition is not exposed by the way this update applies. Hide the update so it stops retrying, or simply ignore the error.

For 0x80070643 errors on non-recovery updates, the cause is usually a broken Windows Update component store, not partition size. The reset steps in our walkthrough for the 0x80073712 / 0x800f0993 update errors clear the same component corruption and resolve those cases.

What to do right now

If 0x80070643 keeps retrying on every reboot, do this in order:

• Open an elevated Command Prompt and run reagentc /info. Read the table above to decide whether you even need the resize.
• If you do need it, back up your important files first; a mistyped partition number in diskpart is unforgiving.
• Follow the resize steps exactly, reading each diskpart line before pressing Enter, and match the partition type (GPT id de94bba4-... versus MBR id 27) to your disk.
• Run reagentc /enable, confirm reagentc /info shows Enabled, then rerun Windows Update.
• If your machine has no recovery partition at all, just hide the update; it does not apply to you.
• If the failure is on a different, non-recovery update, skip partitions entirely and reset the Update component store instead.

Frequently asked questions

Will resizing the recovery partition delete my files?

No, as long as you shrink the OS partition (which only removes free space) and only delete and recreate the small recovery partition. Your personal files live on the OS partition and are untouched. Still, take a backup before running diskpart, a mistyped partition number is unforgiving.

Why does Microsoft not just fix this automatically?

The recovery partition usually sits after the OS partition on disk, so Windows cannot grow it automatically without moving data. Resizing requires shrinking the neighbor first, which Microsoft chose not to do silently on millions of machines. That is why they published manual instructions instead.

Can I use a partition tool instead of diskpart?

Yes. A free partition manager can move and resize partitions with a graphical interface, which avoids the risk of selecting the wrong partition by number. The end goal is identical: give the recovery partition at least 250 MB of free space, then run reagentc /enable.

The update still fails after resizing. What now?

Run reagentc /info and confirm WinRE is Enabled and points to the new, larger partition. If it does not, the recreate step may have used the wrong partition type for your disk (GPT versus MBR). Recheck which scheme your disk uses in Disk Management, then redo the create/format step with the matching ID.