After all your helpful replies I got rid of all my mobis and upgrded Calibre
Something I have been nervous about for ages.
Really pleased.
But I keep thinking should I get rid of any of these also...
AZW3 2685
ORIG AZW3 13
ORIG EPUB 1524
ORIG MOBI 73
PDF 14
Or leave well alone?
And if so, which ones do I really not want?
What do I type in to find them?
Is it the same as removing the Epub?
I value this forums help.