One of my student’s models just disappeared. The project file is there, but it is empty and there is nothing in there. When we look at the revision history it says v.248 (it has been a long project!) but it is not recoverable. It also says “Invalid Date” for the last time that the project was saved. I am sure that he is on the same account as it is shared with his Google Drive Folder and he has shared the model with others as well.