Illustrator Could Partially Read This File

Hi everyone,

I've been working on files with heavy 3D effects and today, they no longer open correctly. I had three files in which I was using a mix of "3D classic" and "Extrude and Bevel" features. While Illustrator was processing things very slowly when ever I'd make any change to a design with a 3D effect, I had no other major issues until today. I went to open up a file, and I got the message "Illustrator Could Partially Read This File. We recovered as much of the file as possible, but some content might be missing. Open to view the recovered file". When I'd open the file, all I'd see was flat images of anything I had saved on an artboard. All my artwork off of the artboards was gone, and I could no longer edit anything. I had five files I was actively working with. Two opened up fine, the other three had that message. All three had 3D effects in them so I assume that's the cause.  I chatted with a senior member of adobe support and he got into my computer remotely. However after opening up the files, he found that they were un-recoverable. I worked several days on these files and the thought of having to recreate those designs, kills me. And it gets even worst. After I chatted with the support person, I decided to start recreating some of my designs in the two remaining files. Those files-again were opening up totally fine. But then about half an hour later, I tried to re-open one of the working-fine files, and I got the same message as the corrupted files and the files opened up with flat images again. This file also had 3D elements in it. So I really think that's the cause!  The file that is still opening up fine has no effects in it. This is incredibly frustrating!! Four days of work- gone. There has to be a solution. I installed Illustrator Beta and saw correct previews of my corrupted files so it makes me think my files are still somehow salvageable. Anyone else run into this issue?