EPUB FixerKDP upload error scanner

Preview a sample EPUB scan report

This is the same report layout you see after upload. Use it to check whether the output is useful before you scan your own EPUB.

Three sample reports below show the three possible outcomes: a checked repair with a download, a report that stops for manual review, and a file that is unsupported by this scanner.

Possible results

Know the boundary before you upload.

Checked repair

Download can appear

Only when EPUB Fixer writes a deterministic structure repair and the repaired EPUB passes the second EPUBCheck run.

Needs review

No checked download yet

Use the affected path, original error, and copy summary for the person editing the EPUB.

Unsupported here

Stop and fix the source workflow

Return to the source export, fixed-layout, conversion, DRM, or editor workflow before scanning again.

Sample 1 of 3

Checked repair — download is available

This sample shows what the report looks like when the repaired file passes the second EPUBCheck run. The download section and retry form appear only in this state.

Scan report

Checked repair available

A checked EPUB download is ready.

The repaired file passed a second EPUBCheck run here, so this copy is ready to test at the platform where your original upload failed.

Download this checked EPUB, then retry the same file.

Use KDP, Kindle Previewer, or EPUBCheck again before treating this copy as final.

Report snapshot

Issues found
3 issues found
Download
Repaired file ready
Repairable
3
Checked changes
OPF identifier wiring, OPF media types, nav.xhtml manifest declaration
Scan statusScan complete
File typeReflowable EPUB
DownloadRepaired file ready
Checked repair changedOPF identifier wiring, OPF media types, nav.xhtml manifest declaration
Repair summary3 auto-fixes were applied and the repaired file is ready for retry.
Second EPUBCheck resultThe repaired EPUB passed the second EPUBCheck run, so the checked download is available.
Retry evidenceEPUBCheck passed, KDP still failed, Kindle Previewer not tried yet, same error
Report IDsample-checked-repair

Checked in this report

  • OPF metadata and package wiring
  • Manifest entries and media types
  • Internal links and resource paths
  • Navigation, NCX, and spine wiring

Recommended order

Use the repaired EPUB for one retry, then save the result.

Use the download below, retry the same file where it failed, then mark the result on this report.

  1. Step 1Download this fileUse the repaired EPUB from this report, not another export.
  2. Step 2Retry it where it failedTry KDP, Kindle Previewer, or EPUBCheck before treating it as final.
  3. Step 3Save what happenedMark passed, still failed, or not tried yet on this report.
Scan another EPUB

  • Status

    Checked repair available

    File to retry
    Repaired EPUB package
    Next owner
    Author
    EPUB Fixer result
    Already repaired and checked here.
    What to record next
    Latest retry evidence: EPUBCheck passed, KDP still failed, Kindle Previewer not tried yet, same error.

Why this download can be retried

Only checked structure changes are listed here.

Use this only if you need to confirm what changed before retrying the repaired EPUB.

Changed

OEBPS/content.opf
Repair type
OPF package identifier
Before
package unique-identifier was missing
After
package unique-identifier="bookid"
Why this was safe
The OPF already had one clear identifier to reuse.
Second EPUBCheck
Second EPUBCheck passed after the repair was written.

Changed

OEBPS/images/cover.png
Repair type
OPF manifest media type
Before
media-type="image/jpeg"
After
media-type="image/png"
Why this was safe
The existing file extension matched one deterministic image type.
Second EPUBCheck
Second EPUBCheck passed after the repair was written.

Changed

OEBPS/content.opf
Repair type
Navigation manifest entry
Before
nav manifest item had no properties="nav"
After
nav manifest item has the nav property token
Why this was safe
The EPUB already contained one clear navigation file.
Second EPUBCheck
Second EPUBCheck passed after the repair was written.

Issue list

TOC and navigation issues (1)

1 issue already has a checked repair. Download the repaired EPUB and retry that file.

The navigation wiring in this group was already changed and then checked again with EPUBCheck before the repaired download was shown.

Next: Try it in KDP, Kindle Previewer, or EPUBCheck, then save whether it passed or still failed.

Affected file: OEBPS/content.opf

Check first
Table of contents declaration in OEBPS/content.opf
Issue
EPUBCheck cannot find exactly one EPUB 3 navigation document declared in the OPF manifest.
Why this can be repaired
Can auto-fix only when one existing nav XHTML file is clearly the intended EPUB 3 table of contents.
Next step
Check which XHTML file is the real table of contents. Add the nav property token only to that one manifest item, and stop if the EPUB needs a TOC rebuild instead of package wiring.
Original error
EPUB 3 nav item is missing the nav property token

Opens the paragraph for declaring nav.xhtml in content.opf and highlights the TOC wiring to check.

Open repair guide

Package and manifest issues (2)

2 issues already have a checked repair. Download the repaired EPUB and retry that file.

The package or manifest wiring in this group was already changed and then checked again with EPUBCheck before the repaired download was shown.

Next: Try it in KDP, Kindle Previewer, or EPUBCheck, then save whether it passed or still failed.

Affected file: OEBPS/content.opf

Check first
OPF package identifier in OEBPS/content.opf
Issue
The OPF package does not tell EPUBCheck which dc:identifier is the book's main identifier.
Why this can be repaired
Can auto-fix only when the OPF has one clear dc:identifier to use as the book identifier.
Next step
Open content.opf, find the package tag, and point unique-identifier only to one existing dc:identifier id that is clearly the book identifier. If ISBN, UUID, retailer, or draft ids compete, choose manually before editing.
Original error
OPF_048 Package unique-identifier is missing

Opens the paragraph for adding the package unique-identifier pointer. Use it with the affected OPF file shown in this report.

Open repair guide

Affected file: OEBPS/images/cover.png

Check first
OPF manifest media type for OEBPS/images/cover.png
Issue
The OPF manifest says this file has one media type, but the file extension or content points to another type.
Why this can be repaired
Can auto-fix when the same packaged file is clearly correct and only the OPF media type is wrong; if the asset itself may be wrong, it still needs source review.
Next step
Check the manifest href, keep the same packaged file only when it is the intended asset, and change media-type to the real file type without renaming or swapping the file blindly.
Original error
OPF_029 Manifest media-type does not match the file extension

Opens the paragraph for this media-type mismatch and highlights the content.opf change to check.

Open repair guide

Sample 2 of 3

Needs manual review — no checked download yet

This sample shows what the report looks like when issues require a decision before any automatic repair can run. The affected path and next step are visible, but no download appears.

Scan report

Review needed before retry

A checked download is not ready for this EPUB.

Resolve the remaining issues before you expect a repaired download.

Review the remaining issues before you retry this EPUB.

Start with Link and anchor issues: Affected file: OEBPS/nav.xhtml. Use the decision flow below to keep the paths, errors, and next step together while you fix the source file.

Review manual issues

Report snapshot

Issues found
2 issues found
Download
Not available
Needs review
2
Scan statusScan complete
File typeReflowable EPUB
DownloadNot available
Checked repairNo checked repair was created
Repair summary2 manual-review issues need attention before retrying KDP.
Report IDsample-needs-review

Checked in this report

  • Navigation, NCX, and spine wiring
  • Internal links and resource paths
  • XHTML structure
  • OPF metadata and package wiring

Recommended order

Start with the issue that still needs a decision.

Use the open issue as the handoff: affected file, original error, and the exact thing someone must confirm before editing.

  1. Step 1Open the blockerUse the highlighted issue group as the first checklist.
  2. Step 2Prepare the handoff summaryKeep the path, validator message, and next check together for the person editing the EPUB.
  3. Step 3Use the report detailsUse the report details before changing the source file.

  • Scan result

    Manual anchor decision

    Affected file
    OEBPS/nav.xhtml
    Who should handle it
    EPUB editor
    Can EPUB Fixer handle it here?
    No, confirm the intended target before editing or uploading again.
    What to check next
    You need to confirm the intended target before editing.

  • Scan result

    Manual navigation decision

    Affected file
    OEBPS/toc.ncx
    Who should handle it
    Author or EPUB editor
    Can EPUB Fixer handle it here?
    No, confirm the intended target before editing or uploading again.
    What to check next
    You need to confirm the intended target before editing.

Issue list

Link and anchor issues (1)

You or a formatter need to confirm the intended target for 1 issue before another upload.

EPUB Fixer only auto-fixes this group when one file path or one anchor target is the clear match.

Next: Use the issue details below to confirm the intended file path or reading anchor before you change the EPUB or export again.

Affected file: OEBPS/nav.xhtml

Check first
Broken internal link anchor in OEBPS/nav.xhtml
Issue
A link points to an anchor id that does not exist in the target XHTML file.
Why this needs review
Needs manual review when the missing fragment belongs to a footnote, backlink, repeated heading, or any link where the reader destination is not obvious.
Next step
Split the link at #, confirm the target file exists, then compare the fragment with real ids in that file. Only retarget the link when one existing anchor is clearly the same reading location.
Original error
RSC-012: file 'OEBPS/Text/chapter-02.xhtml' referenced in 'OEBPS/nav.xhtml' with fragment identifier '#intro-section' could not be found

Opens the paragraph for this missing anchor and highlights what to check before editing the link.

Open repair guide

TOC and navigation issues (1)

You or a formatter need to confirm the intended target for 1 issue before another upload.

EPUB Fixer only auto-fixes this group when one nav file, NCX file, or spine target is the clear match.

Next: Use the issue details below to confirm the intended nav file, NCX file, spine order, or TOC target before you change the EPUB or export again.

Affected file: OEBPS/toc.ncx

Check first
EPUB file path: OEBPS/toc.ncx
Issue
The EPUB navigation, NCX, or spine wiring needs review.
Why this needs review
Open the NCX and OPF spine wiring before changing the EPUB.
Next step
Use the affected path and original error to decide whether the file, OPF entry, or link target should change.
Original error
NCX-001: The NCX identifier does not match the package unique-identifier.

Use this guide to check navigation files and spine/NCX wiring before rebuilding the table of contents.

Open repair guide

Sample 3 of 3

Unsupported by this scanner — stop and fix the source

This sample shows what the report looks like when the EPUB is outside the current repair scope. The report explains why the scan stopped and what to fix before uploading again.

Scan report

Needs source export fix

This file is not supported by this scanner.

The scan stopped at fixed layout. Try a text-first EPUB 2 or EPUB 3 file without fixed-layout pages, DRM, image-first content, or source/conversion files.

Use a supported EPUB export before scanning again.

The scan stopped at fixed layout. Try a text-first EPUB 2 or EPUB 3 file without fixed-layout pages, DRM, image-first content, or source/conversion files.

Check unsupported files

Report snapshot

Issues found
1 issue found
Download
Not available
Unsupported
1
Scan statusNot supported
File typefixed layout
DownloadNot available
Checked repairNo checked repair was created
Repair summaryNo checked repair was created because this file is outside what EPUB Fixer can safely repair today. Export a supported reflowable EPUB before scanning again.
Report IDsample-unsupported

Checked in this report

  • OPF metadata and package wiring
  • Unsupported scope checks

Recommended order

Fix the source export before scanning again.

This upload stopped before EPUB structure repair. Fix the source export and scan the EPUB again.

  1. Step 1Read the stop reasonConfirm why this file did not reach a checked repair.
  2. Step 2Fix the source exportUse the source tool or EPUB package step named in the report.
  3. Step 3Upload againScan the corrected EPUB when the package is ready.

  • Stop reason

    Unsupported preflight stop

    Affected file
    fixed-layout.epub
    Who should handle it
    Source export or EPUB editor
    Can EPUB Fixer continue here?
    No, this is outside what EPUB Fixer can safely repair today.
    What to do next
    The scan stopped at fixed layout. Try a text-first EPUB 2 or EPUB 3 file without fixed-layout pages, DRM, image-first content, or source/conversion files.

Issue list

Package and manifest issues (1)

1 issue is still outside what EPUB Fixer can safely repair today.

Use the issue details below to confirm the intended OPF, manifest, or package target in your source export or EPUB editor.

Next: Leave this report and use your source export or EPUB editor to correct the OPF or package file manually before scanning another EPUB.

Affected file: OEBPS/content.opf

Check first
EPUB layout metadata in OEBPS/content.opf
Issue
This is a fixed-layout EPUB. EPUB Fixer handles reflowable EPUB structure issues, not fixed-layout page repair.
Why this stops here
Not supported here because changing fixed-layout files requires layout judgment.
Next step
Export a reflowable EPUB if that is possible, or fix the fixed-layout file in the source tool or EPUB editor.
Original error
Fixed-layout EPUB metadata detected

This report found a fixed-layout EPUB, so the guide opens the matching unsupported item.

Open fixed-layout guide

Use your file

Ready to check your EPUB?

Upload the EPUB that failed KDP, Kindle Previewer, or EPUBCheck to see the affected paths, repair decisions, and next steps for your own file.

Upload your EPUB

After you retry, save the result here.

Try the downloaded EPUB in the tool that failed before. Mark passed, still failed, or not tried yet.

EPUBCheck retry result

EPUBCheck

KDP retry result

KDP

Kindle Previewer retry result

Kindle Previewer

If it still failed, was it the same error or a new one?

Sample retry results on this report.

EPUBCheck: Passed · KDP: Still failed · Kindle Previewer: Not tried yet · Same error

Saved on this report: 2026-05-04 08:15 UTC

Saved platform error line: KDP still reports the same navigation warning after retry.