Windows & BSOD · critical

How to fix0x80070643

Windows Update Error 0x80070643 (WinRE size too small)

What this error means

Windows Update Error 0x80070643 (WinRE size too small) is a critical-severity Windows operating system issue. This error is triggered when Windows Update fails to install the recovery partition update (often KB5034441) due to the Windows Recovery Environment (WinRE) partition size being too small. It's also often linked to system servicing stack corruption. Use the steps below to track down and fix the cause.

Before you begin

Save open work and back up important files. Note any recent driver or hardware changes. If Windows cannot start, use the startup guide first.

Work through these checks

0 of 3 complete
01Manually resize the WinRE partition to allocate at least 250MB of additional space.

Manually resize the WinRE partition to allocate at least 250MB of additional space..

Use the instructions for your exact device and operating system. Check the manufacturer’s documentation before changing firmware, hardware, or system settings.

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02Re-enable WinRE using reagentc command line utility.

Re-enable WinRE using reagentc command line utility..

Use the instructions for your exact device and operating system. Check the manufacturer’s documentation before changing firmware, hardware, or system settings.

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03Reset Windows Update component files.

Reset Windows Update component files..

Use the instructions for your exact device and operating system. Check the manufacturer’s documentation before changing firmware, hardware, or system settings.

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Possible causes

  • Insufficient free space in the Windows Recovery Environment (WinRE) partition.
  • Corrupted recovery image files.
  • System servicing stack corruption.