Thank you for your answer, Charles. Unfortunately my problem, due to my rash stupidity, is more serious and, alas, I think, without solution. I overwrote my text and, without realising it, I saved the overwritten file. Only after closing it and opening it again I realised that my text had disappeared because I had deleted it, overwriting only two lines. Thank you anyway. I'm trying to rewrite the lost chapter, following my scattered handwritten notes. A couple of days of extra work and a good lesson for the future