Missing Layer Information

Hello, 

I had a project set up that involved multiple layers and masking. I worked the files as usual bottom to top with a few adjustment layers and whatnots. After saving the files (8 total) 3 of those files lost all of there photogrpahic information when reopend minutes later. The layers/work I created within photoshop are still there but the actual pixel information from the photos vanished entirely. Those 3 files look like the image attached. Also when viewed in finder as a thumbnail the file displays all of the information properly.