title_body: Epub -> Mobi/Azw3 conversion (calibre) , Kindle App doesn't show cover no matter what I am trying to convert my ebooks from epub format to mobi/azw3, in order to put them onto my Kindle App and Paperwhite. Everything works fine except the book covers don't show up in kindle app. There's no description also, so it's impossible to recognise which book I'm opening. 
  I am using Calibre (osX) for the conversion.
  
  
  All my epub ebooks come with covers as the first page.
  I am not trying to convert from PDF, I know it can result in unpredictable outputs.
  When I make the conversion in calibre, everything seems to work fine. The computation produces three output files, the azw3 file, a jpeg file for the cover and a metadata file. 
  
  
  What I tried:
  
  
  I used the "Send to device" function in calibre after the conversion, (and I made sure I was sending the newly converted azw3 file, not the epub), and the cover doesn't show up un Kindle App.
  I tried to use the "Save to disc" function, same result as before.
  I tried to manually edit the book cover downloading it again from amazon.com through calibre, and then reconverting again azw3 to azw3 to make sure the cover bound to the file. It doesn't work.
  I also tried to manually put the azw3 file into the kindle library folder.
  I tried the same things as before with the mobi format. Same result. 
  
  
  I really don't know what to do anymore. Any help would be highly appreciated.
upvoted_answer: Everything works fine except the book covers don't show up in kindle app. 
  
  
  Unfortunately, that's the default behavior, because the Kindle for PC/OSX app will only display covers for "personal documents," i.e. ePubs converted with Kindle Previewer/KindleGen, or books bought from Amazon.
  
  AFAIK, Calibre adds a fake ASIN and changes other metadata items so that books no longer appear in the Personal Documents folder. However, this change also causes the book to be displayed without a cover in the Kindle for PC/OSX apps.
  
  
    Everything works fine except the book covers don't show up in kindle app. There's no description also, so it's impossible to recognise which book I'm opening.
  
  
  To display the book titles, click the hamburger icon (≡) in the Kindle app toolbar.