Sorry for this stupid question but : some weeks ago I have lost my configuration file (corrupted too when I had to kill the IDE which was lagging) and now I get a corrupted project. Do you see any reason (apart from a virus) by chance ? Lack of memory ??
No it wasn't : my IDE was lagging previously while working in Rapid debug mode. But it was far earlier from saving this project and I can't remember a problem when saving this one.
It is probably more a problem with my SSD (I will change it). I won't spend your time more and do thank you a lot for the tip to open the project.