Where are my backup pictures and documents aftter the sw upgrade?

I backed up my pictures and the WD IBook drive (MAC) asked me to upgrade the sw.  I did the upgrade, but now I cannot see any of my backup pictures or documents on my WD external drive.  Please help. I am in panic!  I have over 10 years worth of family pictures. 

Please help!!!

Try exploring the external hard drive manually and you should be able to see the files.