The Truth About RelativityOne Load Files: Debunking the Myth

In the world of e-discovery, load files are the unsung heroes that make the exchange of data between platforms possible. They organize, structure, and translate massive amounts of information into a format that review tools can understand. Among these, the .DAT file—often referred to as a “Relativity load file”—is the most recognized.
But here’s where confusion sets in: many people believe that .DAT load files belong exclusively to RelativityOne. That’s simply not true.

What Is a .DAT Load File?

A .DAT file is a structured text file made up of delimiters and field metadata that map data into a document review database. In plain terms, it’s the roadmap that tells the review software where each piece of metadata—like custodian, file path, or date created—belongs.

When bundled together, a typical Relativity load set includes:

• A .DAT file (metadata)
• An .OPT file (image cross-reference)
• Images, OCR text, and native files

This combination allows review platforms like RelativityOne to correctly organize documents, link images to metadata, and make the entire data set searchable.

A Standard, Not a Secret

The term “Relativity load file” has become common because RelativityOne is one of the leading review platforms in the e-discovery industry. However, the .DAT format itself is not proprietary. It did not originate with Relativity and it is not exclusive to it.

In fact, the .DAT and .OPT formats were first used by Concordance, one of the earliest review tools, long before RelativityOne existed. Over time, these formats became the industry standard—adopted by nearly every major platform, including RelativityOne, iPro, Everlaw, GoldFynch, and Nuix Discover.

This means a .DAT load file created in one system can typically be loaded into another with minimal field mapping adjustments. It’s a universal e-discovery language, not a proprietary code.

Debunking the Myth: RelativityOne Doesn’t “Own” the Format

One of the biggest misconceptions in e-discovery is that only RelativityOne can generate or read .DAT load files. In reality, any major document review or production platform can export or import .DAT files.

Service providers frequently edit or remove certain fields when preparing load files for different systems. For example, some platforms require an extra identifier field, while others do not. These minor adjustments don’t change the core structure or compatibility of the .DAT file—it remains the same standardized format that’s been around for decades.

Even older formats like .LST and .DII, developed by other review tools, are still supported by RelativityOne and other platforms, proving just how open and flexible these standards truly are.

Why the Myth Persists

The confusion often comes from branding. Because RelativityOne is a market leader, its name has become synonymous with load files—just like people say “Google” when they mean “search.” But the truth is that the .DAT format belongs to the industry, not a single company. It’s a neutral, open, and collaborative standard used across the e-discovery ecosystem.

Why It Matters

Understanding this distinction matters because it affects how data is shared, migrated, and reviewed across systems. Recognizing that load files are universally compatible allows legal teams and service providers to:

• Avoid unnecessary vendor lock-in
• Move data seamlessly between platforms
• Ensure interoperability and defensibility
• Save time and cost during productions and migrations

In other words, being informed about what a load file really is—and isn’t—empowers you to make smarter choices in your e-discovery workflows.

See Load Files in Action

If you’re curious about how load files are created, edited, and imported in RelativityOne and other platforms, we’d love to show you. Our team can walk you through a live demo, demonstrating how .DAT and .OPT files are used in real-world review environments and how truly universal these formats are.

Reach out today to schedule a session and see why .DAT load files are a standard everyone can use—not just RelativityOne.