Thank you for such fast response!  The thing is, I replaced both drives.  The original drives were operating as one drive, rather than two.  I don't know if that is RAID or not.  Sorry.   I'm willing to reformat,  but the thing is that it was reformated before I reinstalled on the new drives.  I'm dubious that another reformat would help at this point.  I appreciate your suggestion and will take it under serious advisement.  I hope you can understand my hesitation to do so, having just got my drives finally reinstalled over a couple of months.  (I have a lot of stuff and locating the  backups was a real pain and major investment in time.)  Think I'll wait and see if anybody else has some other alteratives before I act on your advise (which makes a lot of sense to me.)
 

Jeremy