ERROR_INSTALL_FAILURE 0x80070643

Error code 1603 · HRESULT 0x80070643

WINDOWS

Fatal error during installation.

Also searched as: 0x80070643, error 1603, fatal error during installation, windows update error 0x80070643, installation failed 0x80070643, KB5034441 0x80070643

Windows troubleshooting diagram: Device Manager warning and a system file scan
Windows errors: check drivers, system files and Event Viewer, in that order.

What it means

Error 1603 / 0x80070643 "Fatal error during installation" is the generic failure returned by Windows Installer (MSI) packages and by Windows Update when an update installer fails. It is common with .NET Framework updates, Microsoft Defender definition updates, Office and many desktop apps. In early 2024 it also appeared widely for the Windows Recovery Environment update KB5034441 on PCs whose recovery partition was too small.

Applies to: Windows 10, Windows 11

How to fix ERROR_INSTALL_FAILURE

  1. Restart the computer and run the installer or Windows Update again; a pending reboot is a frequent cause
  2. Run the installer as administrator and make sure no other installation is running in the background
  3. Run the built-in troubleshooter: Settings > System > Troubleshoot > Other troubleshooters > Windows Update > Run (Windows 10: Settings > Update & Security > Troubleshoot > Additional troubleshooters)
  4. For .NET Framework updates, run the Microsoft .NET Framework Repair Tool, then retry the update
  5. For Defender or Office updates, repair the product from Settings > Apps > Installed apps > the app > Modify or Advanced options > Repair
  6. Create an installer log for MSI packages with msiexec /i package.msi /l*v C:\install.log and search the log for 'return value 3' to find the failing step
  7. Repair system files from an elevated Command Prompt or Terminal (Admin): run DISM /Online /Cleanup-Image /RestoreHealth first, then sfc /scannow, and restart when both finish
  8. If KB5034441 fails with 0x80070643, it relates to the WinRE partition size; follow Microsoft's published guidance for resizing the recovery partition and back up first, since partition changes carry risk

Why it happens

1603 hides the real cause, which can be a pending restart, insufficient permissions on the install folder, a damaged previous installation of the same product, corrupted .NET or Windows Installer components, or a lack of space in the target partition. The verbose MSI log shows the exact action that failed.

FAQ

Can I ignore a Windows Update that fails with 0x80070643?

For one-off definition or optional updates you can wait for the next release, but repeating failures should be fixed because security fixes stay uninstalled.

What does error 1603 mean in an installer?

The MSI package hit a fatal error and rolled back. The verbose log reveals which custom action or file caused it.

Related errors

ERROR_INSTALL_ALREADY_RUNNINGERROR_INSTALL_OPEN_PACKAGE_FAILEDERROR_INSTALL_RESOLVE_DEPENDENCY_FAILEDERROR_INSTALL_FAILEDERROR_INSTALL_USEREXITERROR_INSTALL_SUSPENDERROR_INSTALL_SERVICE_FAILURE

Source: Microsoft WinError.h · fixes written and reviewed by the editors (see our editorial policy)

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