[AlanHK]

You see this from mobi files when there are blank lines that may have been formatted as headings, and then converted by something which splits it at those heads. Giving you a bunch of blank files.

Anyway, if there are chapter heads as h tags, then I just merge all these files into one. Then use S&R to delete the blank headings, then insert a split marker before each remaining heading. Then split at markers and regenerate the TOC.

Take care if there are links, like footnotes. Merging may break those.