What must the requesting party show to prove prejudice from lost ESI before sanctions are awarded?

When electronically stored information (ESI) is lost, a court does not automatically impose sanctions. Under the framework of the U.S. Federal Rules of Civil Procedure governing the failure to preserve ESI, the requesting party generally must first establish a chain of threshold conditions, and one of the most contested is prejudice — a showing that the loss actually harmed its ability to prove or defend the case. This page addresses the federal civil standard; rules differ across state courts and other countries, so always check the controlling jurisdiction.

The Threshold Before Prejudice

Prejudice is typically reached only after the requesting party shows that:

• The lost ESI should have been preserved because litigation was reasonably anticipated;
• The party that held it failed to take reasonable steps to preserve it; and
• The information cannot be restored or replaced through additional discovery.

If the ESI can be recovered from backups, other custodians, or alternative sources, there is no compensable loss — and the prejudice question never arises.

Demonstrating Prejudice

Because lost data is, by definition, unavailable, courts do not demand that the requesting party reconstruct exactly what was destroyed. Instead, the party usually must offer enough to let the court reasonably infer that the missing ESI was relevant and would have mattered. Persuasive showings often include:

• Evidence of relevance — the role the data played in events at issue (for example, communications during a key period or transactions in a relevant system);
• Gaps in the record — specific factual questions that cannot now be answered because the source is gone;
• Corroboration — testimony, metadata, surviving fragments, or third-party records suggesting the content and significance of what was lost; and
• Materiality to claims or defenses — how the absence impairs proof of a specific element, not merely inconvenience.

Mere speculation that “something helpful” existed is rarely enough.

Why the Bar Differs by Remedy

Courts calibrate relief to the harm. Measures designed to cure prejudice — such as additional discovery, cost-shifting, or allowing argument about the loss — generally require a finding of prejudice but not bad intent. The most severe sanctions (adverse-inference instructions, dismissal, or default) typically require a separate finding that the party acted with the intent to deprive another of the information, a higher bar than prejudice alone.

For related concepts and obligations, see e-discovery.