0x80070643 on KB5034441: the recovery partition is too small to patch
0x80070643 on the WinRE servicing update means the recovery partition lacks free space. Resize or rebuild that partition, then reapply the update.
Windows RE update fails with 0x80070643 – recovery partition too small
0x80070643 blocks the WinRE servicing update when the recovery partition lacks free space. Resize or recreate the partition, then reapply the update.
0x80070643: .NET Framework Setup Ends With a Fatal Installation Error
0x80070643 on a .NET Framework install points at a damaged runtime or blocked assembly write. Run the .NET Repair Tool, then reinstall in the correct order.
0x80070643 during an Exchange CU: setup fails and rolls the server back
0x80070643 and MSI 1603 abort an Exchange CU part way through. Learn how to read the setup log, find the failing task and finish the upgrade.
Windows Defender update error 0x80070643: security intelligence will not install
Defender error 0x80070643 blocks security intelligence updates and leaves detection stale. Here is the real cause and the fix that clears it.