Hi Robert,
Usually, Error code 0XC1900101 happens when a security application blocks the installation of an update. These security applications are but is not limited to anti-virus softwares, proxy applications, and 3rd party firewalls. A driver of an unnecessary hardware could also prevent the installation of an update. To troubleshoot this issue, we recommend disabling all your security applications temporarily. Removing all unnecessary hardwares before updating is also required. As much as possible, only connect the keyboard and mouse on your PC. After meeting all these conditions, kindly try updating your PC again.
Let us know how things go.
Regards.