Step#1 - Capture Process Monitor Trace 1. Download and run Process Monitor. Leave this running while you perform the next steps.
2. Try installing the update just like you have in the past.
3. Stop Process Monitor as soon as it fails. You can simply do this by clicking the magnifying glass on the toolbar as shown below.
4. Select the File menu...Save... and save the file to your desktop. This is likely the default location. The name (unless changed) will be LogFile.PML. This is fine.
5. Zip up and attach the LogFile.PML file as well as your CBS.log
Was able to install KB4103720 manually. Ran procmon, the file ended up being over 200MB. I have enclosed the complete CBS file. This is all it is, it was purged as part or earlier troubleshooting, hence being so small. I will try updates again this weekend.