EPUB FixerKDP upload error scanner

EPUB error guide

Check EPUB after Vellum export

Scan a Vellum EPUB before upload to check TOC links, OPF data, cover metadata, manifest entries, and ZIP packaging for KDP, Previewer, or EPUBCheck blockers.

Scan EPUB structureSee an example report

Scan the EPUB to check file paths and see what can be repaired or needs manual review. Your original EPUB stays unchanged.

No signup before the scan report.Your original file is not overwritten.Repair download only after EPUBCheck passes again.

Need fixed-layout, DRM, or source-file help? Check unsupported or review-first EPUB cases.

Match these report titles

  • Check EPUB after Vellum export
  • Vellum EPUB failed KDP upload
  • Vellum EPUB Kindle Previewer validation issue
  • Vellum EPUB TOC, cover, OPF, link, or ZIP blocker
  • Validate Vellum EPUB before KDP upload

Start here

Check the Vellum EPUB output, not the Vellum project.

Upload the .epub that Vellum produced. The scan does not open or edit the Vellum project; it checks the packaged files KDP sees, such as content.opf, nav.xhtml, toc.ncx, cover references, chapter links, and the ZIP wrapper.

Matched

What it means

KDP never sees the Vellum project. It sees a ZIP package with OPF metadata, navigation files, XHTML chapters, images, CSS, manifest entries, and container data.

Matched

Can it be fixed automatically?

A checked repair is possible when the export has one clear mismatch, such as a nav declaration, cover-image property, manifest item, media type, path, or ZIP order that can be changed without guessing the book's intent.

Matched

What to check next

Upload the .epub exported by Vellum, not a PDF, project file, or source manuscript.

Matched

What not to assume

It cannot edit the Vellum project, design the book, choose chapter order, rebuild a missing TOC from author intent, restore missing images, fix paperback PDF output, or decide KDP review outcomes.

1. Example report output

What a Vellum export report should show.

A useful report tells you whether to touch Vellum at all.

Uploaded file

The .epub exported from Vellum, not the Vellum project or a PDF proof.

Navigation check

Whether nav.xhtml, toc.ncx, OPF manifest entries, and TOC targets point to the same chapters.

Reference check

Footnote anchors, chapter links, cover-image metadata, image paths, and CSS paths inside the export.

Decision

Retry upload, use a checked EPUB repair, return to Vellum, or stop because the file is outside this scanner.

The report should keep you from re-exporting blindly when only one packaged reference is wrong.

2. Next step

Choose retry, checked repair, or Vellum re-export.

Use the affected path before changing headings, notes, cover art, or Vellum export settings.

Retry

No supported structure blocker is found.

Try Kindle Previewer or KDP again, while remembering that platform review is separate from EPUB structure.

Checked repair

One packaged reference is wrong.

Use repair when the OPF, nav, cover, path, media type, or ZIP change is obvious and does not change the book.

Re-export

The source decides the fix.

Return to Vellum when headings, TOC hierarchy, footnotes, missing images, or visible layout need author judgment.

3. Concrete path example

A Vellum EPUB can fail because a generated TOC link points at an old anchor.

The chapter opens, but a strict validator may still reject a stale fragment id.

Vellum export:
File: final-vellum.epub

Report:
Source file: OEBPS/nav.xhtml
Target file: OEBPS/Text/chapter-06.xhtml
Missing anchor: #chapter6
Decision: manual review unless one replacement heading id is clearly the same chapter

If Vellum regenerates ids on export, fix the TOC or heading source in Vellum rather than patching random anchors.

Quick decision

Decide whether this is a Vellum export structure issue.

Use it for the Vellum EPUB file after export. Do not use it as a Vellum layout editor.

Good fit

You have the Vellum .epub that will go to KDP.

The scanner can inspect navigation wiring, OPF metadata, chapter links, footnote anchors, cover wiring, manifest entries, and ZIP packaging.

Manual fit

The report names a path but the choice belongs in Vellum.

Use the path as a checklist, then correct the chapter, note, cover, or TOC source before exporting again.

Not this tool

You need layout, PDF, or KDP account help.

Paperback PDF, visual styling, pricing, categories, review status, and KDP listing problems are outside this scan.

Common situations

Common Vellum EPUB export cases.

Start with the Vellum file that actually failed or is about to be uploaded.

Matched

KDP rejects the Vellum EPUB but the book opens locally.

A reader can open the chapters even when KDP rejects a stale TOC target, missing manifest item, or bad cover declaration.

Scan the same export and start with the first affected path.

Matched

The Kindle Go To menu or TOC looks wrong.

Vellum may generate both nav.xhtml and toc.ncx, and the OPF still has to identify the intended navigation file.

Check navigation wiring before changing chapter headings.

Matched

The cover image is inside the EPUB but not treated as the cover.

The image file can be present while the OPF cover metadata or cover-image property points somewhere else.

Scan cover wiring before replacing artwork.

Vellum export phrases to check

Check EPUB after Vellum export: scan the exported Vellum EPUB for KDP, Kindle Previewer, EPUBCheck, TOC, nav.xhtml, OPF, links, cover wiring, manifest, media-type, container, and ZIP blockers.

Where Vellum EPUB blockers usually appear

An author has a Vellum-exported EPUB and either wants a pre-upload check or has a KDP, Kindle Previewer, or EPUBCheck rejection on that exact file.

What it means

A Vellum book can look right while one package link is still wrong.

Vellum-related blockers usually come from generated TOC anchors, OPF navigation declarations, cover-image wiring, missing packaged resources, media-type mismatches, or ZIP wrapper mistakes.

Before you edit

Check generated navigation, anchors, and cover wiring before exporting again.

If the book looks fine in Vellum, avoid changing the manuscript first. Check whether the failure is just a stale TOC target, cover property, manifest entry, or missing packaged file in the exported EPUB.

  1. 1Upload the .epub exported by Vellum, not a PDF, project file, or source manuscript.
  2. 2Keep the Vellum project so you can re-export if the report says manual review.
  3. 3Check the report for OPF, nav.xhtml, toc.ncx, XHTML links, anchors, image paths, manifest entries, cover wiring, media type, container.xml, or ZIP packaging.
  4. 4Use checked repair only when one structural change is clear and the repaired EPUB passes EPUBCheck again.
  5. 5Return to Vellum when the fix depends on chapter structure, TOC hierarchy, missing assets, notes, or visible formatting.
  6. 6Handle KDP account, pricing, categories, review, paperback, and cover upload tasks outside this scanner.

Why KDP checks it

Why Vellum EPUB exports still need package validation.

KDP eBook file formats

KDP supports EPUB files that meet Kindle Publishing Guidelines and recommends checking the file with Kindle Previewer before upload.

EPUBCheck

EPUBCheck checks EPUB 2 and EPUB 3 files against the official rules and reports package, markup, link, and file-reference problems.

EPUB 3.3 package rules

The OPF file is the EPUB's map: metadata, file list, reading order, and navigation wiring. KDP and EPUBCheck use it to decide whether the book package is coherent.

Repair example

When a Vellum EPUB issue can be repaired here.

Before / after example

Before: nav.xhtml exists but content.opf does not mark it as the EPUB navigation document. After: the manifest property can be aligned when nav.xhtml is clearly the intended file and EPUBCheck passes again. Before: no reliable TOC exists; fix the Vellum source.

Ready to retry?

Upload the Vellum-exported EPUB for a structure scan.

Choose the Vellum .epub you plan to upload. If the scan finds a safe structural repair, the repaired download appears only after that file passes EPUBCheck again.

Upload EPUB to scan

FAQ

Questions authors ask after Vellum EPUB export.

Can EPUB Fixer check a Vellum EPUB before KDP upload?

Yes. Upload the Vellum-exported reflowable .epub. The report names the internal path and says whether the next step is retry, checked repair, Vellum re-export, or unsupported.

Should I export from Vellum again before scanning?

Scan the file you already plan to upload or the file KDP rejected. Re-export after the report points to a Vellum-side TOC, heading, footnote, image, or layout decision.

Can this fix Vellum layout or paperback PDF problems?

No. It checks the EPUB package after export. Vellum styling, print PDF, cover design, and KDP listing work stay outside this scanner.

Does a clean scan mean KDP will accept my Vellum EPUB?

No. A clean scan only means no supported EPUB structure blocker was found here. KDP upload, review, account, and content checks remain separate.

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