NG fails on one partition only: error E0BC0002

I have NG 15 set up to back up five different partitions on my computer on a regular basis.

 

Recently, one of the five has suddenly started failing to back up.

 

Error messages:

A test that safeguards the integrity off the program unexpectedly.  Precondition failed, Snap Volume GetEnabledStatus: .\SnapVolume.cpp(189): volume

UMI: V-0-2987-19)

Error e0bc0002 running job: Drive Backup of FDrive (F:\)

 

I stress that the backups of all my other partitions still work fine, so essentially my NG installation must be functioning - it is something about this particular partition that is troublesome.  The partition that does not work is but one partition of a RAIDed hard drive that contains other partitions that back up successfully.

 

I have tried many things:

 

1) Deleted the problem partition and recreated it (hopefully that would have fixed any errors in the partition table)

2) Followed the directions found here to delete all of NG's *.pqh and *.pqj files from the Program Data directory of C:, then recreated all of my NG backup jobs from scratch

3) Run the NG installation disk and told it to repair my installation

4) Run the FixInstall batch file.

 

This backup worked fine for years before it started failing.  Need ideas for what to try now.  Thank you.