you will not lose anything. calibre will not move any of the books from the MY documents\My Books folder that sony uses, it will only make a COPY of them i n its own library if you tell it to.
It will not delete any books on the T2 unless you tell it to & even them it will probably say - are you sure.
But close the sony reader software when you are using calibre & vice versa, to be extra cautious
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