Lost share price history

It seems that I just can't win! I have now discovered that all of my share price history vanished at the time of reloading Home & Business 2016. Fortunately, after reading the help file, I was able to recalculate every transaction and some prices have returned, but only those relating to a buy or sell transaction - the rest have vanished! How do I get those back? I have had this happen several times over the years, but why does it occur at all? Surely after all the comments and discussion about this issue over the years, Reckon would have fixed the problem??