What is WU-0x80073701?
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.
Common 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.
Step-by-Step Fix Guide
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1
Run the DISM StartComponentCleanup command to purge outdated and corrupted update logs.
"Run the DISM StartComponentCleanup command to purge outdated and corrupted update logs." targets missing assembly metadata required for verifying cumulative update configurations, one of the documented causes of WU-0x80073701.
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2
Use 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." is worth trying when missing assembly metadata required for verifying cumulative update configurations turns out to be the culprit.
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3
Check the CBS.log file to identify and manually reinstall the missing package identifiers.
If earlier steps didn't help, "Check the CBS.log file to identify and manually reinstall the missing package identifiers." directly addresses missing assembly metadata required for verifying cumulative update configurations.
Commands & Diagnostics
dism /online /cleanup-image /startcomponentcleanup
sfc /scannow
Frequently Asked Questions
WU-0x80073701 is most often triggered by missing assembly metadata required for verifying cumulative update configurations. Other reports point to corrupted Component-Based Servicing (CBS) log references in the system registry and interrupted installation steps from previously attempted updates as contributing factors.
Most WU-0x80073701 reports resolve after "Run the DISM StartComponentCleanup command to purge outdated and corrupted update logs". The rest of the guide above is there for the cases that don't.
WU-0x80073701 is a high-severity error. It won't damage your PC instantly, but repeated occurrences usually point to a deeper problem worth addressing soon.
Usually. WU-0x80073701 is fixable with the steps above; a full Windows reinstall is rarely necessary unless everything else has failed.
Sometimes. Microsoft regularly releases patches that fix known BSOD triggers including WU-0x80073701. Make sure Windows is fully up to date via Settings → Windows Update before attempting more advanced fixes.
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