Originally Posted by kyteflyer
Its probably because Calibre stores metadata in a separate file along with the cover. Under normal circumstances (eg if you buy an ebook and download from somewhere) all of that is contained within a single file. Calibre doesn't alter the content of that file so if you have a book which has no cover, or one which is different to the one you decided you wanted, *thats* what you get when you d/l from dropbox to any reader.
One way around it is to save out your entire Calibre library making sure the metadata is saved to each file (I did it once, sorted by author then series) and upload that to your dropbox/sugarsync/box/idrive/whatever instead. The difference being that you will need to repeat the process for every new book you add to the Library, instead of everything being automatically updated as you add to Calibre itself.
Although, on re-reading your post... i think I have misunderstood, and now I really dont understand whats going wrong for you. oh well, i tried.
Hey - thanks for trying! I'm over halfway through my library now, cleaning things up and getting them more to my liking. It's given me a good excuse to essentially do some spring cleaning with my Calibre library. And it's definitely nice to be able to access my library from anywhere now - Marvin gave me the kick in the pants I needed to finally make that switch.
After researching it some, I realize that if I'd recognized what had happened right away I probably could've fixed it right after I moved the library to Dropbox. But like I said, it's nice to get this housekeeping done.