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Most Amazon KDP upload failures come from one of four places: book details that do not match the files, an invalid manuscript format, print or ebook layout problems, or a cover that fails technical checks. Identify the format and exact message first, compare your metadata, correct the original manuscript or cover file, then upload again and approve the matching KDP preview. Do not overwrite a working upload until you have saved the current files locally.
This guide covers Kindle ebooks, paperbacks, and hardcovers, including ISBN, language, conversion, margin, bleed, font, image, cover, and preview errors. The instructions reflect KDP help guidance available in October 2026; platform requirements can change, so open the linked KDP pages when a requirement is critical to your publication schedule.
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Start by identifying the format and the exact error
KDP validates an ebook differently from a paperback or hardcover. Print books have separate interior-manuscript and cover uploads, while an ebook has its manuscript and cover sections. Before changing anything, open the title in Bookshelf and write down the exact wording of the warning, the format selected, and the file that triggered it. A vague description such as “KDP rejected my book” is not enough to choose the right fix.
- Confirm the format. Decide whether the message belongs to a Kindle ebook, paperback interior, hardcover interior, or cover.
- Capture the message. Note whether KDP identifies a page, field, file, or check. Preserve a screenshot if the warning disappears when you leave the page.
- Separate validation from review. A previewer error is a file or layout problem. A post-submission manual review can identify additional issues and may arrive by email with instructions.
- Use the matching tool. Online Previewer and Kindle Previewer are for ebook rendering and quality checks; Print Previewer is for print interiors; Cover Studio checks and helps create covers. An original editor is required for problems those tools cannot directly repair.
| Book component | First tool to use | What it can reveal | Where the correction is made |
|---|---|---|---|
| Kindle ebook manuscript | Online Previewer; Kindle Previewer for additional device and app rendering | Language mismatch, spelling issues, image quality, unsupported layout, and rendering problems | Some highlighted issues can be handled in the preview panel; otherwise edit the source manuscript and upload it again |
| Paperback or hardcover interior | Print Previewer | Margins, trim, bleed, fonts, page navigation, and other interior errors | Edit the original layout file, export a compliant file, upload, and preview again |
| Print cover | Cover Studio and the print preview | Resolution, safe-zone placement, spine treatment, and cover-size problems | Fix the cover source or use Cover Studio’s Auto-fix where offered, then save and preview |
| Metadata or ISBN | Book Details and the issuing ISBN agency record | Differences in title, author, imprint, language, or ISBN | Correct the KDP details or the source files, then allow synchronization time when an agency record was recently changed |
KDP’s Upload and Preview Book Content guidance explains which upload and preview fields apply to each format. Use it as the starting point when the message is unclear.
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Check book details before changing the layout
Metadata inconsistencies can stop a technically perfect file. Compare the title, subtitle, author name, series information, language, ISBN, and imprint entered in KDP with every corresponding occurrence in the files. Inspect the title page, copyright page, headers, cover text, running matter, and any series or edition statement. Matching punctuation, capitalization, spacing, and word order matters when KDP compares records.
Title, author, series, and language
Use the exact edition information for the book you are uploading. A subtitle in Book Details that is missing from the title page, an author name with a different middle initial, or a language selection that does not describe the manuscript can trigger a validation or conversion problem. If you intentionally use a different public-facing form of a name, make sure the edition’s metadata and files still describe the same book rather than two versions.
ISBN and imprint mismatches
When you supply your own ISBN, compare the number and its registered title, author, and imprint with the record at the issuing agency. KDP says an ISBN or imprint problem is a typical cause of the message “Please fix the highlighted issue” when no field is visibly highlighted. Copying the agency’s details and pasting them into KDP can prevent an extra space, punctuation mark, or spelling difference.
If you recently changed the record at Bowker, KDP says registration of the change can take up to five business days. Do not repeatedly alter your manuscript while waiting for a metadata update; first confirm that the agency record is correct, then allow that stated period for KDP to receive it. See KDP’s ISBN troubleshooting instructions.
Verify the manuscript file and export settings
The correct file type depends on whether a print interior uses bleed. KDP’s manuscript-file guidance requires a PDF for a print interior with bleed. A no-bleed print interior may use PDF, DOC, DOCX, RTF, HTML, or TXT, subject to language-specific exceptions. If a conversion file is larger than 650 MB, KDP says the conversion fails. Exporting from the original layout program to a clean PDF is usually safer than repeatedly converting an already converted file.
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Before uploading a PDF
- Open the exported PDF on your computer and inspect it page by page. KDP specifically advises checking that a generated PDF looks as intended.
- Confirm the selected trim size matches the document’s page size and that bleed is configured consistently with the KDP setup.
- Check the inside margin and gutter for the final page count, not just the first few pages.
- Verify that fonts are embedded and that special characters have not changed during export.
- Inspect images at their placed size, not only at a small zoom level.
- Look for accidental blank pages, duplicated pages, missing page numbers, hidden objects, stray text boxes, and content outside the intended page area.
- Make the correction in the original program and, where required, save a new PDF for the next upload. Do not try to repair a margin or font problem only inside the previewer.
Ebook source checks
For an ebook, confirm that the language selected in Book Details matches the manuscript. KDP’s conversion guidance identifies unsupported accent marks and other characters that can appear as boxes or jumbled text. Search the source for unusual symbols, copied characters, and fonts or glyphs that the selected language does not support. Replace unsupported characters with supported equivalents, then reconvert and preview.
Keep the manuscript in an editable source format. If the previewer shows a problem that it does not highlight or cannot edit, the only dependable path is to fix the source document, generate a new upload file, and run the preview again. A preview screenshot is evidence of the symptom, not a substitute for correcting the underlying file.
Use the correct previewer and read every flagged item
Online Previewer for ebooks
After uploading an ebook manuscript, open Online Previewer and use its quality panel. KDP describes checks for spelling and image quality and indicators for language mismatch and unsupported layout cases. Review the book at several screen sizes or device views rather than looking only at the first page. Follow the previewer’s navigation to each flagged location.
Some corrections can be made in the preview panel, but a panel edit does not fix the source file you keep on your computer. If the same manuscript is later uploaded again, the original defect can return. For any issue that is not directly editable in the panel, change the manuscript, export or convert it again, upload the replacement, and rerun the complete preview.
Kindle Previewer for rendering across devices
Kindle Previewer can supplement Online Previewer by showing how the ebook renders in different Kindle devices and applications. Use it to inspect page breaks, navigation, images, tables, and character rendering at more than one screen size. Treat it as a rendering check, not as permission to ignore a KDP quality warning.
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Print Previewer for paperback and hardcover interiors
Open Print Previewer after uploading the interior and cover. KDP says it checks for errors such as margins, cover size, and fonts and can navigate to affected pages. Work through every required correction before submitting. A file that looks acceptable in a desktop PDF viewer can still fail because a trim, gutter, font, or bleed setting is not compatible with the selected print edition.
KDP also performs a manual check after submission. If that review finds a problem, KDP emails instructions. Follow the specific message, correct the original source, upload the replacement, and approve the revised preview. Print files can also be checked with an ordered physical proof, which is useful for catching clipping, contrast, or page-turn problems that are difficult to judge on screen.
Fix the print errors Print Previewer commonly exposes
Trim size, bleed, margins, and gutter
Trim size is the final cut size of the book; bleed is extra artwork that extends beyond the trim so a full-page image reaches the edge after cutting. A mismatch between the KDP setup and the layout document can shift every page. Confirm the trim selection first, then verify that bleed is used only where the design requires it. Check the inside margin and gutter on facing pages, especially in longer books where the binding consumes more interior space.
Fonts and text flow
Missing or unembedded fonts can substitute a different typeface, change line lengths, and create new page breaks. Embed fonts during export when the layout program supports that option. Recheck headings, footnotes, tables, running headers, and page numbers after embedding because a font substitution can move text even when the page count appears unchanged.
Images and resolution
KDP’s print guidance uses 300 DPI as the image-resolution benchmark. A picture that is sharp at a small preview size may become blurry when printed at its placed dimensions. Replace low-resolution originals or reduce the placed size in the source document. Do not rely on a previewer’s apparent sharpness at one zoom level; inspect photographs, line art, and full-bleed backgrounds separately.
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Pagination and hidden content
Scroll through the entire interior for blank pages that were not intended, missing pages, duplicated chapters, clipped text, and objects hidden behind other objects. Check the first and last page as well as chapter openings, because section breaks and different page styles often create errors there. Remove stray text boxes and off-page objects before exporting a fresh PDF.
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Language mismatch
If KDP reports that the manuscript appears to be in the wrong language, compare the language in Book Details with the actual text and with the language of the file selected for upload. Correct the details when the manuscript is right; select or prepare the correct manuscript when the details are right. Preview after either change, because language metadata can affect conversion and quality checks.
Boxes, scrambled accents, and unsupported characters
Boxes or jumbled characters usually indicate an unsupported character, accent, symbol, or font glyph. Search the source rather than deleting random text from the converted file. Replace the offending character with a supported form, verify the language support, create a new conversion, and inspect the same passage in Online Previewer and Kindle Previewer.
Spelling and image warnings
Use the Online Previewer quality panel to locate spelling flags and blurry or low-quality images. Correct text in the source manuscript so the change remains in your master copy. Replace an image with a higher-quality original or resize it appropriately, then upload the revised file. If the quality panel does not identify the problem, inspect the source and use the previewer’s device views to locate where the rendering changes.
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Layout that does not survive conversion
Fixed spacing, complex text boxes, unsupported tables, and unusual page-break techniques can reflow in an ebook. When a layout issue is not highlighted or cannot be edited in the preview tool, simplify or rebuild that section in the source manuscript. Reconvert rather than attempting to patch individual converted pages, and check navigation and images after the new upload.
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Fix a cover that will not submit
Open Cover Studio’s Checks panel and read each item before changing the artwork. KDP’s examples include a blurry image likely below 300 DPI, important elements placed outside the safe zone in the bleed area, and an incorrect spine treatment. Cover Studio offers Auto-fix for some issues, but inspect the result instead of accepting it blindly.
Resolution warning
If Cover Studio identifies a blurry image, replace it with a higher-resolution source or reduce how large it appears on the cover. KDP uses 300 DPI as the print image-resolution guidance. A sharper source is preferable to software upscaling, which can make an image larger without restoring detail.
Safe-zone and bleed placement
Keep titles, author names, barcodes, and other important elements inside the safe zone. Artwork may extend into bleed, but text or essential details placed there can be cut off. Move those elements inward in the cover source, regenerate the cover, and run the Checks panel again.
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Spine text and page count
Spine text is unsupported on books under 79 pages. If a short book triggers a spine-text warning, remove the spine text rather than trying to force it into the template. For longer books, confirm that the cover’s spine treatment corresponds to the final interior page count and the selected binding.
Save drafts deliberately
Cover Studio drafts do not auto-save. Save a draft regularly while working, and preserve a copy of the current cover before replacing an upload. If a browser session closes or a cover is overwritten, an unsaved draft may not be recoverable.
Preserve files before replacing an upload
Download or otherwise preserve the current manuscript, cover, and source files before uploading a correction. KDP warns that after new files are uploaded, previous versions may no longer be downloadable. Keep a dated folder containing the editable source, the exported PDF or ebook file, the cover, and a note of the KDP settings used for that edition.
- Save the current files locally before opening the replacement workflow.
- Make the correction in the original editor or cover source.
- Export a new file using the format required for the interior and the selected edition.
- Upload the replacement manuscript or cover in the correct KDP section.
- Run Online Previewer, Kindle Previewer, Print Previewer, or Cover Studio as applicable.
- Open the revised preview and inspect the pages or views named in the previous error.
- Approve the corrected preview only after required checks are clear, then submit for publication or review.
Symptom-by-symptom troubleshooting table
| Symptom | First checks | Supported next action |
|---|---|---|
| Language error or the manuscript appears to be the wrong language | Compare Book Details language with the actual manuscript and the selected upload file | Correct the details or manuscript selection, upload again, and preview the result |
| Strange boxes or jumbled characters in an ebook | Search the source for unsupported characters, accents, or glyphs | Replace unsupported characters, reconvert, and preview the affected passage again |
| Ebook spelling or blurry-image warning | Open the Online Previewer quality panel and follow each location | Correct text or replace the image in the source file; use the source for issues the panel cannot edit |
| Print Previewer reports margins, fonts, trim, bleed, or cover errors | Check trim size, bleed, margins, gutter, font embedding, image resolution, and cover dimensions | Fix the original file, create a compliant PDF where required, upload it, and run Print Previewer again |
| Cover will not submit in Cover Studio | Read every Checks-panel item; inspect resolution, safe zone, bleed, and page count for spine text | Resolve blocking errors or use Auto-fix where offered, save a draft, and preview before submitting |
| ISBN error with no visible highlighted field | Compare ISBN, title, author, and imprint with the issuing agency record | Correct the metadata; if Bowker was recently changed, allow up to five business days for KDP to register it |
| You need the previous source file after uploading a replacement | Check your local dated backups | Preserve originals before every replacement because KDP says earlier versions may no longer be downloadable |
A final pre-submission checklist
- The format in Bookshelf is the format you are actually publishing.
- The title, subtitle, author, series, language, ISBN, and imprint match between KDP, the interior, and the cover.
- Any self-supplied ISBN matches the issuing agency record exactly; recent Bowker edits have had up to five business days to register.
- A print interior with bleed is a PDF, and a no-bleed interior uses an accepted file type for its language.
- The manuscript conversion file is no larger than 650 MB.
- Trim size, bleed, margins, gutter, fonts, images, pagination, and blank pages have been checked in the source file.
- Print images meet the 300 DPI guidance at their placed size.
- Ebook language, spelling, characters, images, navigation, and layout have been reviewed in Online Previewer and, when useful, Kindle Previewer.
- Print interiors and covers have been reviewed in Print Previewer; cover blocking errors are cleared in Cover Studio.
- The current manuscript, cover, exports, and settings are backed up before replacement uploads.
- The revised preview has been approved, and you are prepared to respond to any separate manual-review email from KDP.
KDP’s official instructions for the individual checks are available in Fix Paperback and Hardcover Formatting Issues, Troubleshooting File Conversion Errors, and Guide to Kindle Content Quality. These file and formatting checks do not represent every account-specific review hold; when KDP provides a separate account or policy message, follow that message rather than changing an otherwise compliant file at random.
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