Norton Ghost 15 and hidden files

I had occasion to restore my system with a Norton Ghost 15 backup from three months ago.  All went well and I was very glad to have had the backup available.

 

However, I also have another backup program which backs things up automatically from day to day and stores those backups on my external drive.  When Norton Ghost restored my system recently I went into my external drive to review what was there from the other backup program so that I could take some of the files and add them back to my restored drive.  What I discovered was that the old files backed up by my other backup program were invisible even though I knew that they were there taking up over 1TB of space.  I was able to find files by using Windows Search and that showed the files in the results at the end of the scan.  I was then able to read them and place them into my restored system.  Previous to my Norton restore I was able to view them in my other backup program but not after the recent Norton restore.  Would anyone know why the Norton restore made these files invisible and have any suggestion as to how I can make them visible again?  Thank you.