What counts as 'not reasonably accessible because of undue burden or cost' under Rule 26(b)(2)(B), and who bears the burden of proof?

In federal civil litigation, the Federal Rules of Civil Procedure recognize that not all electronically stored information (ESI) is equally easy to retrieve. Rule 26(b)(2)(B) addresses sources of ESI that a party identifies as “not reasonably accessible because of undue burden or cost.” Understanding this provision helps legal, records, and IT teams scope discovery sensibly and document their reasoning.

What “not reasonably accessible” means

The rule does not list specific technologies. Instead, it turns on the practical effort and expense required to retrieve, restore, and produce data — not merely whether the information is relevant. In practice, courts have treated as potentially “not reasonably accessible” data that exists but is difficult to access in its current form, such as:

• Backup or disaster-recovery media designed for restoration of whole systems rather than targeted search
• Legacy or obsolete formats requiring restoration on outdated hardware or software
• Fragmented, deleted-but-recoverable, or heavily compressed data needing forensic recovery

By contrast, active files on current systems are generally considered reasonably accessible. The distinction is fact-specific and depends on the actual burden, not a fixed category.

Who bears the burden of proof

The responding party — the one resisting production — bears the initial burden of showing that the identified source is not reasonably accessible because of undue burden or cost. A general objection is not enough; the party should support the claim with specifics about effort, expense, and process.

If that showing is made, the burden shifts. The requesting party may still obtain the information by showing good cause, considering proportionality factors found elsewhere in Rule 26(b). Even when good cause exists, the court may set conditions — for example, cost-shifting, sampling, or limits on scope.

Practical takeaways

• Map where ESI lives and how hard each source is to retrieve before disputes arise; strong information governance makes the accessibility analysis easier to support.
• Document the burden and cost with concrete facts, not conclusions.
• Raise accessibility early, ideally during meet-and-confer and at the Rule 26(f) conference.

Note that these principles govern federal civil cases. State courts and other countries apply different rules and standards. For related concepts, see our e-discovery topic hub.