When I install KB5066586 to Windows 10 Enterprise LTSC 17763 , it returns 2147942423

Hello Fiona,

Thank you for posting question on Microsoft Windows Forum!

The error code 2147942423 (0x80070570) during KB5066586 installation might indicate that the update package is corrupted. As your EventViewer log accurately reports in German. Datenfehler (CRC - Prüfung) (Data error / Cyclic Redundancy Check). This means the file Windows is attempting to read is either corrupted or became mangled while being transferred.

Looking at your command line, the issue is heightened because you are installing it directly from a network or mapped storage drive (**Z:**). Installing large .msu Windows updates directly over a network share via wusa.exe can easily trigger CRC errors due to minor network drops or packet loss. You can try to copy the file windows10.0 - kb5066586 - x64_...msu from your Z:\ drive. Paste it onto a local drive on the target machine (e.g., into C:\Temp). Please note: If Windows throws an error while copying the file to your C:\ drive, the file stored in your Z:\ repository is definitely corrupted and needs to be replaced. Then run the installation from the local C:\Temp\ folder.

If running it locally still yields a CRC error, the file inside your repository might be corrupt. The suggestion here is to fetch a fresh, uncorrupted file. Go to the official Microsoft Update Catalog. Search for KB5066586. Download the specific version for Windows 10 Version 1809 for x64-based Systems (which corresponds to your LTSC 17763 build). Then replace the broken file in your RSD_PatchRepository with this newly downloaded file.

In case, a fresh, local file still fails with a CRC error, the corruption might be residing within your local Windows component store rather than the patch file itself. Run the following commands sequentially in an Administrative Command Prompt to repair the OS.

• DISM.exe /Online /Cleanup-Image /RestoreHealth
• sfc /scannow

Once both processes complete successfully, you can restart the system and try installing the local patch file again.

Hope the above information is helpful! If it is. Free feel to hit "Accepted" for benefitting others in community having the same issue too.