Blender Imports Dissapear!

Hey Guys!

Yes, i am new to Unity. I am sure the problem is with me, but my blender files are disappearing. I will import them one day, and they work fine. I add a collider. Then when I close the program, and open it back up, the blender imports (.fbx) are gone. They still show up in the projects column, but when I drag them into the Scene, all that is there is their collider box. But with blender imports that i have not added colliders to, they show up fine. And with some of my older imports, with colliders, they show up fine too. Its really annoying that all my important files are disappearing. Help would be greatly appreciated!

My Problem was after I added the capsule collider to my blender object and put that object in a new prefab, I deleted the original prefab. So now, I have a folder marked originals!