A PDF can carry two documents at once: the pages you see, and a layer of machinery you don’t — reviewer comments pinned to paragraphs, sticky notes from your editor, fillable form fields, document bookmarks, live design layers. Screen readers and office workflows love that machinery. A printing press can’t use any of it, and KDP’s review process handles it the blunt way: strip it, flatten it, or bounce the file.
What KDP is actually saying
KDP’s published submission guidelines take each species in turn:
- Annotations: “Annotations are information added to PDFs that are not intended to print. Examples can include mark-ups, sticky notes, comments, etc. As annotations are not intended to print, they will be removed during the file review process, possibly causing a visible change to the book.” The risk hides in that last clause: if a reviewer’s mark-up was covering something — or a note was placed over art — removal changes what prints.
- Layers: the same guidelines group layers with transparency — flatten “all transparent objects and layers in the native file before submitting,” with a rejection if their review-side flattening isn’t possible. Live layers also carry a visibility risk: what a layer shows on your screen depends on its saved state, and the press prints the state it receives.
- Form fields, bookmarks, and marks: KDP’s manuscript-saving guidance, as summarized in current formatting references, asks for files with no crop marks, trim marks, bookmarks, comments, or annotations, and transparent objects and layers flattened in the native file rather than at export. Interactive form fields have no meaning in a printed book and are treated as defects to remove, not features to preserve.
| Stowaway | Where it usually comes from | What KDP does |
|---|---|---|
| Comments / sticky notes / mark-ups | A review copy circulated to an editor or beta readers, then exported | Removed in review — “possibly causing a visible change” |
| Live layers (incl. hidden ones) | InDesign/Illustrator exports with layers preserved; layered template files | Attempts to flatten; rejects if it can’t; color shift possible |
| Form fields | Workbook PDFs built with fillable fields; form tools | Not printable — must be flattened to static content |
| Bookmarks & document links | Word exports carrying the navigation pane’s bookmarks | Strip at export; harmless on screen, unwanted in a print file |
Check it yourself
- Comments: open the PDF in Acrobat/Reader and open the Comments panel — the count should be zero. Sticky-note icons visible on any page are annotations, full stop.
- Layers: the Layers panel should either be absent or show a single flattened result. Multiple layers — especially any switched off — mean the file isn’t flattened.
- Form fields: Tools > Prepare Form (Acrobat) will detect fields if any exist; a blue highlight wash over page areas in Reader is the giveaway.
- Bookmarks: check the Bookmarks panel; a print file needs none. (This is about the PDF’s internal bookmarks — your book’s own table of contents page is content, and stays.)
Can’t tell what your PDF is carrying? The free check opens your actual files and inventories the machinery — layers, annotations, fonts, transparency, encryption — plus the geometry checks, reported in plain English within 48 hours. Get the free check →
How to fix it
In Word
Before exporting: delete all comments (Review > Delete > Delete All Comments) and accept or reject every tracked change — a document with unresolved mark-up exports its annotations’ cousins. In the PDF options, leave document-structure/bookmark creation off for the print file. Full settings: the Word export guide.
In InDesign
Export with the PDF/X-1a:2001 preset and “Create Acrobat Layers” unchecked: the output is a single flattened layer set with no interactive elements — the same export that solves the transparency problem. Settings in the InDesign export guide.
In Acrobat Pro
Print Production > Preflight offers fixups to flatten annotations and form fields into the page content and to discard interactive elements. Flatten form fields only when you want their current values printed as static text — flattening makes the entered text permanent and un-editable.
For workbooks
Design the print edition with blank lines and boxes drawn as graphics, not as form fields. A fillable PDF is a fine digital product; the KDP edition needs the same pages rendered static.
The honest limit
Stripping this machinery is safe exactly when the machinery was decoration on top of finished pages. If your workflow genuinely stored content in it — text that lives only in a comment, art on a hidden layer, answers typed into form fields — flattening and removal will lose it, and no checker can tell the difference between your content and your clutter. Inventory first (the check above), then clean. And note the boundary of this fix: it produces a clean print file, which is one species of correct — trim, margins, fonts, and the rest of the 13 checks still apply.
Or send us the files — the check is free
Email your interior and cover PDFs and we'll tell you exactly what's wrong — in plain English, free, within 48 hours. If it does need fixing, the by-hand fix is $19 and we redo it free if KDP rejects it for a formatting issue we were hired to fix. We rebuild files to be compliant with KDP's published spec — that's the promise we can keep.
Prefer the whole library in one file? The KDP Rejection Field Guide (free PDF) collects every guide, table, and the 13-point checklist.
More from the Help Library
- The KDP & IngramSpark Help Library — all guides & tools
- Transparency error — flattened files, shifted colors
- Password-protected PDFs — the locked-file rejection
- Fonts are not embedded — how to check and fix
- InDesign → KDP: presets, bleed marks, and font embedding done right
- Word → KDP: the two settings that prevent the classic Word rejections
- The free rejection check — all 13 checks at once