Windows 10: Error at end of Backup

I very recently upgraded my HP All in One running Windows 8.1 Pro to Windows 10 Pro. Now at the end of my daily backup, I'm receiving a consistent error (see below).

Error: Failed to exclusively access a backup file during consolidation. Make sure the file is not opened in other applications.

The only application that might have this file is TIH 2015 (build 6613). The backup is going to an external USB hard drive. I have worked in computers (programming and as a service tech) for about 25 years. I've not yet finding anything that may have the file open. I disabled my virus and malware / spyware application to see if either one was the culprit. Neither was. I'm still receiving the error.

I look forward to hearing from you guys.