It can occur if the update directory is corrupted. Pleased follow the steps below:
1. Disable the Windows Update Service (Settings > Control Panel > Administrative Tools > Services). Just stop the service.
2. Navigate to: C:/Windows/
3. Find the folder named: “SoftwareDistribution”
4. Rename that folder to something like “SoftwareDistribution.old”
5. Create a new folder called “SoftwareDistribution”
6. Go back to your Services panel and start the Windows Update service 7. Rerun Windows Update
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