materials will not preview in windows 8

[Bridget Gaddis]

I am working with AutoCad architecture.  I downloaded the latest materials library and am able to select materials in nxt and put them in my project but the libraries don't preview in the file manager so I must load every material into the project to see what it looks like.  How can I get it to preview in the file manager.  I just shows a red ball.

[Roy Hirshkowitz]

I would attempt to find the offending material first.  If and when you find it-- I'd love to see it.

[Kevin Lockwood]

I did start the process. I sorted by date and worked one file at a time. I could see that as I drug, a transparent thumbnail appeared. All went well until about half way through the directory. I still couldnt tell the file, but I have the list narrowed down. 

Not sure if its related, but my pc freaked out this morning doing a "refresh/bounce back and forth from desktop to start" loop. didnt give me time to click anything. finally got task manager up and found a "WINDOWS THUMBNAIL EXTRACTION.." loop under status.  Finally got in enough to run restore and got it working again. I think (from searches) was from a windows update. 

I'm scarred to go play with icons for a while :) i just tried and its still crashing the materials folder.