Everything that I’ve created turn invisible in composition view

Hi,

I was recently making a video that contains many vectors. All the vectors were imported as illustrator files in after effects. Everthing went normally for a few days until on day when I opened the after effect file, everything in the composition view went invisible. I said invisible because I can still see their adjustable outlines when I let the time line run; however there is no imagine showing. It was just a blank sheet. I tried to render the composition, forcing it to rerun the images, but every time I do it, it will render to the very end and tells you that there is an error without any explanations. Once you click okay, the whole after effects shuts down. I am guessing it might be the fact that there are too many vector files in the composition or I add too many complex movements on my vector files in the composition. I have noticed the render memory was kind of big. It was 16GB. Other than that, I didn't notice anything abnormal.