Diskeeper reported that the \$Extend\$UsnJrnl [Excluded] file size of 872 GB on a 10 GB partition. Diskeeper helpdesk identified problems with OS upgrades regarding \$Extend\$UsnJrnl, however could not address the file size anomaly. Ticket closed. After a little research, I discovered a native command line utility called Fsutil. After executing this utility the problem is resolved.

Note: Do not perform this process on a domain controller.

Screenshots of the original curiosity. Note the extensive, Green – system files.

Those Green – system files is \$Extend\$UsnJrnl and the File size reported exceeds the actual partition size of 10 GB.

Note the Fragmentation percentage is out of range.

Resolution Details
From the CMD prompt, Fsutil USN DeleteJournal /D C:

When complete, if the Indexing Service was running.
Stop and Start the Indexing Service.
Note that the CI is the Indexing Service. The stop error is a result of the non existent journal. When restarted, the Index rebuilds correctly.

Now note the far fewer system files in Green.

The more expected percentage.

Issue resolved.