Lightroom :: Previews Are Corrupting Original Images?

It happened a couple months ago, but I thought it was a bug, and now it's happened again, and now it's corrupting my original files. 
 
Here's what's happening, at least my actions thus far.  Lightroom 4 worked fine and dandy.  No issues whatsoever.  We then upgraded to LR5. 
 
Now, as I'm going in Library tab through images as it's seems to be pulling up an image it shows up with jagged edges and just looks -- corrupted.  So then I look at the file in Finder and now that image can't be opened up in Photoshop, Preview or any other application.  For some reason LR's previews are corrupting the ACTUAL, ORIGINAL images. 
 
Now back a month ago, it happened when it wasn't a big deal, I had the RAW original files backed up, but now, now it's corrupted at least two folders and the original RAW files can't be opened. Here's the summary:
 
-- As for corrupt cameras/disks -- I have files from Hasselblaad and from Canon doing this.  I have many different cards that were used in this. 
 
-- It's only when I opened up in Lighroom 5.  Otherwise files were fine.  JPEG conversions that were made from these images weeks ago were fine. 
 
-- It's happening to one out of every 5 pictures or so.   Which is A LOT OF PICTURES TO BE CORRUPTED. 
 
For the ones that I have backed up, now I have to go figure out which....rename them...etc.  AND HOPE AND PRAY this doesn't happen again. 
 
-- It says it can't open the file. 
 
And then when I go to finder, through lightroom, to RAW image it doesn't work to even bring it in Photoshop. 
 
SO it's corrupting my files so that Photoshop can't recognize them.  NOT all photos are being affected, just the folders I go to in Lighroom.  Any other files in lightroom (from same day/camera) are okay.