Servicing (CBS)
0x80073701
The referenced assembly could not be found.
Failure
What it means
The update references a component that should already be on the device and is not there. Microsoft attributes this to component store corruption caused by a component left in a partially installed state.
Real causes
- A previous update was interrupted and left a component half-installed.
- Component store corruption.
What to do
- Run Dism.exe /Online /Cleanup-Image /RestoreHealth, then Sfc.exe /Scannow, then restart.
- Search
CBS.logfor the assembly name in the failure. It usually names the exact missing component. - If the missing component belongs to a specific earlier update, install that update first.
Where to look
%windir%\Logs\CBS\CBS.log
Checked against Microsoft documentation. Last reviewed 2026-08-20.
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