I just upgraded to 5.5 and have noticed that when I open a book created in 5 that I keep getting forced to save each document within the book and overwrite the existing file. I know there is a "automatic document conversion" option but it's not doing much in the way of automatic conversion as far as I can tell.
Anybody having this issue?
I'm not sure waht you mean by "automatic document conversion." What you see is expected behavior, and a Good Thing.
ID does not automatically change the version of every document you open. It opens previous version files as copies with the same name and (converted) appended for convenience, but the first Save operation is always a Save AS to provide you withthe opportunity to either save a new version (which I recommend) or overwrite the existing file (which I most strongly do NOT recommend).
You should convert your files, then make a new Book, or finish the Book in the old version.