Match the report title.
Look for "Invalid EPUB file" or the closest title above. Keep the original EPUBCheck, KDP, or Kindle Previewer wording if it differs.
EPUB error guide
Invalid EPUB file
Use this when an EPUB file is called invalid, corrupt, damaged, not a valid EPUB, or unreadable by KDP, Kindle Previewer, EPUBCheck, or a publishing platform.
Scan when the message does not name the affected path. The report shows affected paths and repair decisions, not manuscript text.
Fixed-layout, DRM, or source-workflow issue? Check unsupported or review-first EPUB cases.
Match these report titles
- Invalid EPUB file
- Corrupt EPUB package
- EPUB is not a valid ZIP package
- Mimetype, container.xml, OPF rootfile, or package error
Use this guide when
Your message matches "Invalid EPUB file" or one of the report titles above.
Upload if
You have the exported reflowable .epub and need the affected path, file, field, or repair decision before editing.
Handle outside this tool
Use the source tool or publishing workflow for DOCX, PDF, KPF, KCB, fixed-layout, comics, image-first books, DRM, visual design, or KDP listing and approval problems.
Read the scan report
Decide if this report item matches.
Use the report label, affected file, and repair decision together. A matching title alone is not enough if the file path or EPUB structure points to a different problem.
Check the affected file first.
Use the Affected area, Source file, Target file, or Problem type rows before editing OPF, nav, XHTML, CSS, or image paths.
Follow the repair decision.
Repairable means one clear structural change. Needs review or Not supported means use the named file, source project, or platform step.
Keep with your repair note.
Copy these fields from the report instead of rebuilding the fix from memory.
Source file
Target path or field
Original error
Repair decision
Next step
1. Example report output
What an invalid EPUB report should show.
The first useful answer is whether the EPUB wrapper can be repaired or whether the file needs a clean export.
Wrapper check
Is this a readable ZIP package with the EPUB mimetype entry?
Container map
Does META-INF/container.xml exist and point to a real OPF file?
OPF rootfile
Does the rootfile path match the actual package location?
Decision
Repair wrapper, inspect package path, re-export source, or unsupported.
If the package map is broken but one OPF target is obvious, repair may be safe. If the file is damaged or encrypted, use the source export instead.
2. Next step
Choose package repair or clean export.
Invalid EPUB messages are often package-level, but not every damaged file is repairable.
Package check
Use this when the file was manually zipped or renamed.
Mimetype order, compression, and root folder layout are common causes after manual archive edits.
OPF check
Use this when container.xml points to the wrong package file.
A repair can be safe when one real OPF file exists and the rootfile path is just wrong.
Clean export
Use this when the ZIP is damaged, encrypted, or missing core files.
Return to the source project and export a fresh EPUB instead of inventing required package content.
3. Concrete path example
A corrupt-looking EPUB may only have a wrong rootfile path.
The file can contain the book, but container.xml points readers to the wrong OPF path.
Validator: EPUB is invalid: OPF file could not be found. Report: container.xml rootfile path: OEBPS/package.opf Actual OPF file: EPUB/content.opf Decision: safe only if EPUB/content.opf is the single real package file
If several OPF files exist or the ZIP cannot be opened, stop and re-export from the source project.
Quick decision
Decide whether the file is broken or just packaged incorrectly.
Some invalid EPUB files only need a wrapper fix. Others are not safe to repair because required package files are missing.
Good fit
The EPUB is readable but has a package wrapper mistake.
Mimetype, container.xml, OPF rootfile, and simple ZIP ordering issues can be checked and sometimes repaired.
Manual fit
The package has competing OPF files or unclear root layout.
The report can name the candidates, but a person should choose the intended package file.
Not this tool
The file is encrypted, DRM-protected, non-EPUB, or deeply damaged.
Use the original source export or a proper backup instead of trying to patch missing core files.
Start here
Check the EPUB wrapper before editing chapters.
Invalid EPUB often means the package wrapper cannot be opened correctly. Start with mimetype, ZIP structure, META-INF/container.xml, and the OPF rootfile path before touching book content.
What it means
An EPUB is a ZIP package with a required wrapper and a package map. If the wrapper or map is broken, validators may reject the file before checking chapters, images, or links.
Can it be fixed automatically?
EPUB Fixer can help when the wrapper mistake is clear, such as mimetype order, container.xml pointing to one obvious OPF file, or a simple package-root mismatch.
What to check next
Confirm the file extension and source: it should be a real .epub exported by a publishing or formatting tool.
What not to assume
It cannot safely repair a deeply corrupted archive, encrypted EPUB, DRM file, non-EPUB input, missing OPF package, missing book content, or unclear package layout with several competing targets.
Common situations
Common invalid EPUB cases.
Start with the first package layer that fails.
The mimetype file is missing, compressed, or not first.
Manual ZIP tools often package EPUB folders in the wrong order.
Rebuild the wrapper only when the rest of the EPUB package is intact.
container.xml is missing or points to the wrong OPF.
EPUB readers need container.xml to find the package document.
Repair the rootfile path only when one real OPF target is clear.
The file is not a valid EPUB ZIP.
A renamed folder, damaged upload, encrypted file, or wrong source file can look like an EPUB but fail package checks.
Go back to the source tool and export a fresh EPUB.
Invalid EPUB phrases this page can help with
Invalid EPUB file: corrupt EPUB, damaged EPUB, not a valid EPUB, mimetype, container.xml, OPF rootfile, or ZIP package error.
Where invalid or corrupt EPUB messages appear
KDP, Kindle Previewer, EPUBCheck, Apple Books, Google Play Books, or a reader app says the EPUB is invalid, corrupt, damaged, unreadable, not a valid EPUB, or cannot find the package file.
What it means
A file can be invalid because the package map is broken.
An EPUB is a ZIP package with a required wrapper and a package map. If the wrapper or map is broken, validators may reject the file before checking chapters, images, or links.
Common causes include zipping the parent folder instead of the EPUB contents, compressing or misplacing the mimetype file, missing META-INF/container.xml, a wrong OPF rootfile path, damaged ZIP data, encrypted content, or a file that is not really an EPUB.
Before you edit
Check whether the EPUB is packaged like a real EPUB.
A broken ZIP wrapper, missing mimetype, missing container.xml, or wrong OPF rootfile path can stop validation before deeper content errors are visible.
- 1Confirm the file extension and source: it should be a real .epub exported by a publishing or formatting tool.
- 2Check whether the EPUB can be opened as a ZIP package.
- 3Look for the root mimetype entry and whether it is first and uncompressed.
- 4Check META-INF/container.xml and the OPF rootfile path.
- 5Confirm there is one intended OPF package file before repairing container.xml.
- 6Re-export from the source project when required files are missing, encrypted, damaged, or ambiguous.
Why KDP checks it
Why readers and validators reject invalid EPUB packages.
EPUB ZIP container
The EPUB ZIP wrapper must point readers to the OPF file through META-INF/container.xml and keep packaged resources at the paths the book references.
EPUBCheck
EPUBCheck checks EPUB 2 and EPUB 3 files against the official rules and reports package, markup, link, and file-reference problems.
KDP eBook file formats
KDP supports EPUB files that meet Kindle Publishing Guidelines and recommends checking the file with Kindle Previewer before upload.
Can this be fixed safely?
When an invalid EPUB package can be repaired safely.
When automatic repair is safe
EPUB Fixer can help when the wrapper mistake is clear, such as mimetype order, container.xml pointing to one obvious OPF file, or a simple package-root mismatch.
When you need manual review
It cannot safely repair a deeply corrupted archive, encrypted EPUB, DRM file, non-EPUB input, missing OPF package, missing book content, or unclear package layout with several competing targets.
Before / after example
Before: container.xml points to OEBPS/package.opf, but the only OPF is EPUB/content.opf. After: update the rootfile path only when that is the intended package file. Before: the ZIP cannot be opened; export the EPUB again.
Ready to retry?
Scan the invalid EPUB package.
Upload the EPUB when it is not encrypted and still looks like a normal reflowable EPUB package. The report will stop early when the file is outside scope.
Upload EPUB to scanFAQ
Questions authors ask about invalid EPUB files.
Why does my EPUB say invalid or corrupt?
Often the ZIP wrapper or package map is broken. Check mimetype, container.xml, and the OPF rootfile path before editing chapters.
Can a corrupt EPUB be repaired automatically?
Only when the package mistake is clear and the core files still exist. A damaged, encrypted, or incomplete archive should be exported again.
Is renaming a ZIP file to EPUB enough?
No. The ZIP has to follow EPUB packaging rules, including a correct mimetype entry and container.xml package map.
Should I use this for DRM or encrypted EPUB files?
No. DRM-protected or encrypted EPUBs are outside this scanner.