Well, if it ain't our old friend the corrupt file. BTH seems to be plagues with this. An article I wrote a few years ago on Hurricanes in Russia became corrupted when it was alost complete and I had to rewrite the whole blooming thing. This time, my BTH2 file has become corrupted. Lucky I learnt my lesson last time and so have a backup copy saved, but even so I have lost some sections on Bombing, weather and clouds which will have to be rewritten.
Could be worse.