M
0x80073701
Moderate
Microsoft · Windows
The referenced assembly could not be found. A required component assembly or its manifest is missing from the WinSxS store, preventing the update from being applied.
Quick Answer
Error code 0x80073701 on your Microsoft Windows means: The referenced assembly could not be found. A required component assembly or its manifest is missing from the WinSxS store, preventing the update from being applied.. This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
21H222H223H2Server 2019Server 2022
Likely Causes
  1. Component store corruption with missing assembly manifests
  2. Overly aggressive disk cleanup removed required WinSxS components
  3. Previous failed update left the component store in an inconsistent state
  4. Third-party system optimization tools deleted essential assemblies
How to Fix It
1
Run DISM to repair the component store: DISM /Online /Cleanup-Image /RestoreHealth — this is the primary fix for missing assemblies.
2
If DISM fails online, use Windows installation media: Mount the ISO and run: DISM /Online /Cleanup-Image /RestoreHealth /Source:wim:D:\sources\install.wim:1 /LimitAccess.
3
Run sfc /scannow after DISM completes to verify system file integrity.
4
Check the DISM log for specific missing assemblies: Open C:\Windows\Logs\DISM\dism.log and search for the error to identify which assembly is missing.
5
Also check the CBS log: C:\Windows\Logs\CBS\CBS.log — search for 'ERROR_SXS_ASSEMBLY_MISSING' to find the exact assembly name.
6
Restart and retry Windows Update after component store repair.
7
If the issue persists, perform an in-place repair upgrade to completely rebuild the component store.
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
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