[very strange]Why the model disappear in 3 days later?

I can see the model in this part file 3 days ago, but today i cannot see it.

And it cause many mates errors in assembly because the model( lines\\ faces\\etc.) is disappear.

This part file is a STEP file, i save it as a solidworks sldprt file, so it only has a Rawdata.

I hope you could download it and help me, thank you very much.

SolidworksParts And Features