I'm new to Calibre too, not only to this forum, I'm afraid..Anyway, I've been uploading books again, and hope I'll learn and won't make more mistakes.
My OS is OSX 10.5.8 btw.
I'm not sure if it was the upgrading that caused the vanishing scene, but the books are not there, that's the only think I'm sure 'cos on the menu bar I can see only 11 books (I uploaded 9 just now), hope they stay put
I may come back again with more questions, but at least I'm going to get more acquainted with Calibre before I ask any more stupid questions and you guys end up losing patience with be.
Thank you!