How to Review ePUB Files for eDiscovery (Without Creating Extra Work)

19 February 2026 by Carey eDiscovery ePUB PDF file-conversion

Takeaway: To review ePUB files in eDiscovery, convert them to PDF early, try to preserve metadata, and ensure a stable, searchable format to avoid review and production issues.

Every so often, an ePUB file shows up in a document collection, throwing a wrench into the review process.

It makes sense. ePUB is a common format for eBooks, manuals, and digital publications. But when you try to upload one into an eDiscovery platform, things don’t always go smoothly.

Here’s the simple version:

ePUBs are great for reading. PDFs are great for legal review.

If you’re dealing with ePUB files in eDiscovery, let’s walk through what they are, why they create friction, and how to handle them the right way from the start.

What is an ePUB file?

An ePUB (Electronic Publication) file is a digital book format designed to adapt to the reader. The text “reflows”, meaning it adjusts based on screen size, font preferences, and device type.

That’s perfect for eBooks, training manuals, digital reports, and educational materials.

Open the same ePUB on a phone and then on a tablet, and the layout changes automatically. Increase the font size, and the page reshapes itself. Everything is flexible by design.

For readers, that’s convenient.

For legal review, that flexibility can become a problem.

Why ePUB files don’t work well in eDiscovery

In litigation or investigations, consistency matters. Reviewers need stable formatting. Page numbers need to stay put. Productions need to look the same every time they’re opened.

ePUB files weren’t built for that.

Because they’re essentially packaged web content (HTML and XML wrapped inside a compressed file), they don’t have fixed pages. The layout shifts depending on how they’re viewed. That creates issues when you need to cite specific pages, apply Bates numbers, or maintain a clean production set.

Formatting can also look different across viewers. A table might shift. A footnote might move. Images can reposition. What one reviewer sees may not match what another sees.

Most review platforms, including GoldFynch, rely on predictable file structures to support search, tagging, redactions, and production workflows. ePUB files simply don’t process as cleanly as standard formats like PDF.

And that’s where the real impact begins.

How ePUB files can impact the legal process

File format might seem like a minor technical detail. In practice, it can affect time, cost, and defensibility.

If formatting shifts between reviewers, the review takes longer. People spend time figuring out the layout rather than analyzing the content. Multiply that across thousands of documents, and costs rise quickly.

Pagination instability creates even bigger problems. If you reference “page 14” during a deposition, but that page shifts depending on display settings, confusion follows. That’s not a position you want to be in during active litigation.

Redactions can also become risky. Reflowable content means elements can move. Fixed formats reduce the chance of something shifting after it’s been marked.

Then there’s production. If a file behaves unpredictably during export, it can lead to disputes, rework, or additional processing. None of that adds value to your case.

All of this leads to one practical question: how do you avoid these issues altogether?

The fix: Convert ePUB to PDF before upload

The simplest and most reliable solution is to convert the ePUB file to a PDF before uploading it into your eDiscovery platform.

That single step removes most of the instability.

When you convert to PDF, you create a fixed-layout document. Pagination becomes stable. Formatting stays consistent. Every reviewer sees the same version.

PDFs also integrate smoothly with review tools. Searching works as expected, provided the text layer is preserved. Redactions behave predictably. Productions export cleanly.

Instead of troubleshooting formatting during review, you start with a document built for legal workflows.

How to convert an ePUB File to PDF (and what to watch for)

The good news is that conversion is straightforward. The key is choosing the right method and keeping eDiscovery requirements in mind.

Desktop applications (recommended for legal matters)

If the file contains confidential or privileged information, use a local desktop tool rather than an online converter.

One widely used option is Calibre. Calibre is a free, open-source eBook management tool that can convert ePUB files to PDF. Because it runs locally on your machine, it’s generally more secure than uploading documents to a web-based converter.

That said, Calibre is third-party open-source software. It’s not built specifically for legal workflows, so use it with appropriate caution and with internal IT approval.

If the eBook was created using software like Adobe InDesign, there may already be a built-in option to export directly to PDF. In many cases, exporting from the original authoring tool provides cleaner formatting and better control over layout.

Online converters

Online ePUB-to-PDF converters can work for small, non-sensitive files or quick internal needs. However, they may not be appropriate for litigation data.

There’s another issue to keep in mind: metadata preservation.

Preserving metadata during conversion

In eDiscovery, metadata matters. Author information, creation dates, modification dates, and other embedded fields can be relevant to the case.

When converting ePUB to PDF, you should confirm whether the tool preserves metadata.

Calibre allows you to view and manage metadata during conversion, which can be helpful. However, not all online converters consistently preserve metadata. Some may strip it entirely.

If metadata is important to your review or production, test your conversion process before using it at scale.

There’s also a limitation to be aware of: if the eBook is protected by Digital Rights Management (DRM), you may not be able to extract or copy metadata during conversion. DRM restrictions can limit what information is accessible or transferable. In those cases, consult with your legal and technical teams before proceeding.

What to check before uploading to GoldFynch

Before uploading the converted file into GoldFynch, open the PDF and scroll through it.

Make sure the formatting looks right. Check that images and tables appear properly. Run a quick keyword search to confirm the text is searchable and the terms you searched for align correctly with the content. If the document isn’t searchable, don’t worry - GoldFynch automatically runs OCR on it, so your reviewers will be able to locate content efficiently.

Once everything checks out, upload the PDF to your case as you would any other document. From there, you can search, review, tag, redact, and produce it without any special handling.

And that’s really the goal.

Standardize early, review confidently

ePUB files serve a clear purpose in publishing and digital distribution. They’re built for flexibility and reader comfort.

But eDiscovery isn’t about flexibility. It’s about consistency, defensibility, and efficiency.

If you’re working in GoldFynch or managing any eDiscovery workflow, converting ePUB to PDF before upload is the simplest way to avoid avoidable problems. It keeps your review predictable, your productions clean, and your team focused on the substance of the case.

In eDiscovery, small workflow decisions early on can save significant time later. File format is one of them.

Looking for an eDiscovery platform that keeps things practical and predictable? Try GoldFynch

GoldFynch is an easy-to-use eDiscovery service that provides all the tools you need for your eDiscovery review, without installing any software, and is especially built for small to mid-sized law firms. You can sign up for a free trial in seconds without a credit card.

It costs just $27 a month for a 3 GB case: That’s significantly less than most comparable software. With GoldFynch, you know exactly what you’re paying for: its pricing is simple and readily available on the website.
It’s easy to budget for. GoldFynch charges only for storage (processing files is free). So, choose from a range of plans (3 GB to 150+ GB) and know up-front how much you’ll be paying. You can upload and cull as much data as you want as long as you stay below your storage limit. And even if you do cross the limit, you can upgrade your plan with just a few clicks. Also, billing is prorated – so you’ll pay only for the time you spend on any given plan. With legacy software, pricing is much less predictable.
It takes just minutes to get going. GoldFynch runs in the Cloud, so you use it through your web browser (Google Chrome recommended). No installation. No sales calls or emails. Plus, you get a free trial case (0.5 GB of data and a processing cap of 1 GB) without adding a credit card.
It’s simple to use. Many eDiscovery applications take hours to master. GoldFynch takes minutes. It handles a lot of complex processing in the background, but what you see is minimal and intuitive. Just drag-and-drop your files into GoldFynch, and you’re good to go. Plus, you get prompt and reliable tech support (our average response time is 30 minutes).
Access it from anywhere, and 24/7. All your files are backed up and secure in the Cloud.

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