I started a new Rhino session, selected my project file from the welcome window and got the question “Do you want to save Untiteled?”. OK, no problem, why not and I pressed yes. The command tell me "File successfully saved as D:…\ProjectFile.3dm. Wow, 1,5GB project file is overwritten with an empty Rhino file.
I’m glad that I tried to open an older incremental saved file only. It’s not really needed. But this is really dangerous. Please fix it so fast as possible.