You made an ebook, or someone sent you one. Now it won't open, a chapter is missing, or a store says the file has errors. That's an EPUB that is broken inside.
The good news: most problems are small, and you can find them for free. This guide shows how. The quickest way is Ebook Medic, which checks your book, fixes what it safely can and tells you what is left.
What "broken" means
An EPUB is like a zipped folder. Inside are your chapters, your pictures and a few small "map" files. The map files tell a reading app what is in the book and in what order.
A book breaks when the map and the folder don't agree. For example:
- The map lists a chapter or picture that isn't in the folder.
- A file name has spaces or odd letters in it.
- Book details, like the title or language, are missing.
- The files inside are in the wrong order or packed the wrong way.
First, find out what is wrong
Before you fix anything, find the real problem. The rules that stores use come from a free checker called EPUBCheck.
Way 1: Ebook Medic (quickest)
Ebook Medic checks your book with the same rules as EPUBCheck. Then it fixes what it safely can and checks the book again.
- Go to tools.ltd/ebook-medic.
- Click Choose an EPUB, or drag your book into the box.
- Press Check my ebook.
- Read the report. It shows how many errors there were before the fix and after.
- If you are happy with the result, get the fixed ebook.
Your first check each month is free. Getting the fixed file is paid, and you can see the cost on the Ebook Medic prices page before you pay. Your file never leaves your device. The check and the fix run right in your browser.
Ebook Medic fixes things like files listed but missing, file names with spaces, and missing book details. It never makes up a missing chapter. If a problem needs a person, it tells you.
Way 2: Fix it by hand (free)
If you like to do it yourself, these free tools can help.
- Run EPUBCheck. It is free from the group that looks after the EPUB rules. You need Java on your computer to run it, so it suits people who are at ease with a few extra steps.
- Open the book in an ebook editor. Calibre is a free ebook app. Its Edit book window has a Check book tool that lists problems.
- Fix one problem at a time. Start with the first error in the list. One mistake can cause many errors below it.
- Check again after each fix.
Tip: keep a copy of your book before you change anything. Name it clearly, like "My Book v3 original.epub".
Common problems and what to do
| What the report says | What it means | What to do |
|---|---|---|
| A file could not be found | The map lists a file that isn't there | Add the file back, or take it out of the list |
| A file name has spaces | Some apps can't read the name | Rename it with no spaces, and update links to it |
| Missing title or language | The book details are not filled in | Add the details in your ebook editor |
| The first file is wrong | The EPUB was zipped the wrong way | Make the EPUB again from your writing app |
Start from a better file
Many broken books come from a messy first file. If your book began as a PDF, you can turn it into a Word file with PDF to Word. Clean it up in Word, then make a new EPUB from it in your writing app.
Frequently asked questions
How do I know if my EPUB is broken?
Signs include a store refusing the file, a reading app that won't open it, or missing chapters and pictures. A check with the EPUBCheck rules tells you for sure.
Can every broken EPUB be fixed automatically?
No. Simple problems, like a file that is listed but missing, can be fixed. Others, like a missing chapter, need a person. Ebook Medic tells you which problems are left.
Will a store take my book after the fix?
We can't promise that. Stores run EPUBCheck plus their own rules. A clean report is a very good sign, but not a promise.
Is my book uploaded?
No. Ebook Medic checks and fixes the book in your browser. Your file never leaves your device.
Related guides: How to check an EPUB file for errors · KDP EPUB upload error? · More ebook guides