EPUB is a free and open e-book standard by the International Digital Publishing Forum (IDPF), and it is also the most popular eBook format used by almost all the important online eBook retailers except Amazon.
It is precisely because EPUB is free and open, so any people can make a .epub file according to the guideline. But that leads to a problem that not everyone is able to make a perfect .epub file. Even some EPUB books downloaded from online stores might not in standard structure, yes maybe we can read it on their application such as Sony Reader, Kobo Reader, etc., but in fact, it has some issues in file structure. For some worse files, they even can't be opened.
In fact, many damaged .epub file are pretty easy to fix. Just 3 simple steps, we can fix EPUB file and read it perfectly. And I will take an .epub file which is provided by one of our clients as example, who wrote the book and turned it into EPUB himself, and I put this book on the free book introduction page.
A damaged EPUB file can't be opened by reader software
First I load this book into Sony Reader for PC software, and it tells me "The file may be corrupted".
Then I tried to open it with Adobe Digital Editions 2.0, and it also tells me "Errors were encountered in this item".
In the past, I will give up reading the book. But now, we can bring this file back to life with this guide.
Fix the EPUB with 3 steps
1Install a Zip software
There are 2 mainstream free Zip softwares, WinZip and 7-Zip. Unfortunately, they all fail to do the epub-fix job in my tests. So in this post, I will take HaoZip as example, which is also a free Zip software developed by a Chinese company. Click the link to download it on their official site for free.
2UnZip the EPUB file
Use Zip software to unzip the EPUB file. If you can't directly unzip the EPUB file, try to rename the extension name from .epub to .zip, then unzip it.
3Re-Zip the file and change extension name to EPUB
We are not missing any step, yes we just need to zip the folder again. Right click on the unzipped folder, and choose "Add to Archive".
Attention! This is the key-step! Don't directly zip the folder to a .zip file. You should rename the extension name to .epub in zip settings. Then click OK, job done!
Now try to read this fixed EPUB file with Sony Reader or Adobe Digital Editions. Look at the screenshot below, it can be read by ADE perfectly!
FYI: Epubor EPUB to PDF Converter can handle broken EPUB file
The latest version of EPUB to PDF Converter has integrated the EPUB fixing feature. Before the conversion starting, the software will repair the corrupt EPUB file automatically (depends on the extent of damage).
So if you have some damaged EPUB files and accept converting them to PDF, please try to use EPUB to PDF Converter to bring them back to life. Don't worry about paying for the product but it can't convert your damaged EPUB files, 30-day free trial is available to anyone.
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Jonny Greenwood joined Epubor since 2011, loves everything about eBooks and eReaders. He seeks the methods to read eBooks more freely and wants to share all he has got with you.