Unexpected blank pages usually come from hidden breaks, section drift, or inconsistent chapter-start rules. Use this checklist to find the cause, fix it in the source file, and verify it in Previewer.
Decide which blank pages are intentional
Some books intentionally start every chapter on the right-hand page. If that is your design rule, write it down first so you can separate planned blank pages from accidental ones.
If your edition does not need right-hand chapter starts, remove any rule that forces extra blanks.
Lock this decision before final proofing so you do not chase false alarms later.
Look for source-level blank-page causes before export
Check chapter transitions for accidental page breaks, duplicate section breaks, and stacked empty paragraphs.
Make chapter openings consistent so one chapter is not using manual spacing while another uses style-based spacing.
If you imported from DOCX, check copied chapters for hidden breaks left over from older templates.
Keep section behavior simple and consistent
Use section breaks only when you truly need them. Too many section boundaries create more page-number and layout surprises.
If headers, footers, or numbering restart unexpectedly, check section links and numbering settings before you export again.
After a major chapter edit, do a quick chapter-transition check before you run the full Previewer pass.
Validate in Previewer, then fix the source file
In KDP Previewer, inspect every chapter opening plus the page before each chapter. Those are the most common places for accidental blank pages.
When you find a blank-page problem, fix the manuscript structure and export a fresh PDF. Do not patch the final PDF directly.
Give each export a clear file name so you always know which one includes your latest blank-page fixes.