Hello Manon David,
If automated patch deployment is failing with DISM error 0x800F081F (CBS_E_SOURCE_MISSING) or "The source files could not be found", the recommended approach is to execute DISM /Online /Cleanup-Image /RestoreHealth through your management agent under the Local System context and allow access to Windows Update as the repair source whenever internet connectivity is available. Microsoft identifies 0x800F081F as a missing repair source condition and recommends using DISM to repair the component store before retrying patch installation.
For managed devices that cannot reach Windows Update, deploy a command such as DISM /Online /Cleanup-Image /RestoreHealth /Source:wim:\\server\share\install.wim:<index> /LimitAccess, ensuring the WIM source matches the exact Windows edition and build installed on the endpoint. The management platform (Intune, MECM/SCCM, Ivanti, PDQ, etc.) should run the command with administrative privileges and capture logs from C:\Windows\Logs\DISM\dism.log and C:\Windows\Logs\CBS\CBS.log for validation. After DISM completes successfully, trigger sfc /scannow and rerun the failed update deployment to confirm the component store corruption has been remediated. This is the Microsoft-supported method for repairing Windows Update corruption and resolving missing source file failures.
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Thank you.
HL.