Some general tips for WSUS.
Start a Windows Update run from a Windows 10 or Server 2016 client has changed, and is no longer
The files on-disk are Event Tracing for Windows logs, so can’t be viewed directly. Export them:
If the server is not connected to the internet, copy the logs to a machine that is, and is running the same version of Windows, and then run the command there:
Get-WindowsUpdateLog -EtlPath C:\Path\to\etl_files