Windows & BSOD · high

How to fixWU-0x80073701

Windows Update Error 0x80073701

What this error means

Windows Update Error 0x80073701 ranks as a high-severity Windows operating system issue in our database. The referenced assembly could not be found. This error indicates missing or corrupted assembly manifest files inside the Windows Component Store (WinSxS). Another common trigger is interrupted installation steps from previously attempted updates. Work through the steps below in order.

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
01Run the DISM StartComponentCleanup command to purge outdated and corrupted update logs.

Run the DISM StartComponentCleanup command to purge outdated and corrupted update logs..

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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02Use the System File Checker (sFC) tool to scan and restore missing assemblies.

Use the System File Checker (sFC) tool to scan and restore missing assemblies..

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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03Check the CBS.log file to identify and manually reinstall the missing package identifiers.

Check the CBS.log file to identify and manually reinstall the missing package identifiers..

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

  • Missing assembly metadata required for verifying cumulative update configurations.
  • Corrupted Component-Based Servicing (CBS) log references in the system registry.
  • Interrupted installation steps from previously attempted updates.