after restoring my aperture library many of my thumbnails are black unless enlarged or I switch to the spilt screen view, what should I do?

After restoring my aperture library many of my thumbnails are black unless enlarged or I switch to the spilt screen view, what should I do?

I have Aperture 3.6, iMac 2010 with 3.06 processor and 16 Gb of Ram. I use an Iomega 2Tb external drive for Time machine which is what I used to restore

from. I am using OS X 10.10.3 Yosemite.

I have been using Photo but noticed that all of my photos were taken out of Aperture, so I restored them using Time Machine. Many thumbnails are black but some of the photos have color and or image corruption until made larger then they are correct and may not even be as they appear in the thumbnail.

Very strange issue, I an thinking that the Iomega is corrupted somehow. Does anyone have any other ideas or at this point possible solution?

Thank you!