title_body: Can I disable Calibre from doing any conversion? I’d like to use Calibre purely for librarying and sync, and I don’t want it do do any conversion between different ebook formats. It is possible to turn off autoconversion when syncing ebooks with my reader (Kobo Aura H2O)?
  
  To give a specific example, I’d like the Kobo edition of Standardebook’s Crime and Punishment to not be converted to a normal EPUB on loading into Calibre, as it loses a chunk of formatting and the cover when synced. Manually sideloading it into my Kobo retains the cover, chapter progression markers etc etc. This is using latest Calibre (3.7).
upvoted_answer: In Preferences - Adding Books in Adding Actions tab there is a preference Automatically convert added books to the current format You need to click that off. The default is off.