Norton Save & Restore Error E0BB001B

I am using Norton Save & Restore 2.0 Version 2.0.6.26322 to back up my hard drive c: to an external hard drive E:.  I have scheduled weeekly backups that have functioned flawlessly for years.  A few weeks ago, I discovered that the backup would fail and give this error message: 

Error E0BB001B:  Cannot lock volume \\?|Volume {29f17687-17de-11de-91bc-806c6172696f}| because it contains the OS or has an active paging  file.

What can I do to resolve this error and restore my program to its proper function?

Thanks for any help you can provide.