Unexpected File Format Bug Error

I have built a model and successfully save it into a .skp file, however, after I reopen it, I got an “Unexpected File Format” error. I tried everything I know, including importing/renaming etc but the error still exists.

Is there anyone who can help me fix it?

The file is attached in the following address:

I tried the file, but it is missing important data, and I cannot recover anything.