Most evidence is destroyed by accident, on a schedule, by systems doing exactly what they were configured to do. That is precisely why the preservation duty is taken seriously by courts: the failure is usually organisational rather than deliberate, and it is entirely preventable.

When the duty attaches

Not when you are served. The obligation generally arises when litigation is reasonably anticipated — which can be well before a complaint, and is often marked by a demand letter, a threat made in a meeting, a serious internal complaint, or a regulatory inquiry.

The test is objective. The question is not whether anyone said “we should preserve documents”; it is whether a reasonable party in that position would have anticipated a dispute. Businesses tend to date the trigger later than a court will.

What has to be preserved

Anything potentially relevant, in any form. In practice that means more sources than most companies first identify:

  • email and attachments
  • instant messaging and collaboration platforms, including ephemeral or auto-deleting channels
  • text messages, including on personal devices used for work
  • shared drives, cloud storage and version histories
  • databases and structured business records
  • backups, where they hold unique material
  • physical documents
  • devices belonging to departing employees

The categories people miss are consistent: messaging platforms, personal devices, and the laptops of anyone who leaves during the dispute.

The hold notice

A written notice to the people likely to hold relevant material, describing specifically what to preserve, telling them to stop deleting, and requiring acknowledgement. Generic notices produce generic compliance.

Three things follow that matter as much as the notice itself:

Suspend automatic deletion. Email retention policies, messaging expiry settings, and device-retirement processes all have to be paused for the affected custodians. This is where most preservation failures happen, and it usually requires IT to make a change rather than a person to remember something.

Reissue and remind. A notice sent once at the start of a two-year dispute does not hold. Custodians change, new people join, and memories fade.

Document it. Keep the notice, the distribution list, the acknowledgements, and the record of what was suspended and when. If preservation is later challenged, this is the evidence that answers it.

What happens when it fails

Sanctions scale with fault and prejudice. At the lower end, a court may order additional discovery or shift costs. Where a party was negligent and the other side is prejudiced, remedial measures may follow. Where material was lost with intent to deprive the other side of it, the most serious sanctions become available — adverse-inference instructions, exclusion of evidence, or terminating sanctions.

The practical damage often exceeds the formal sanction. A preservation failure becomes a story about the party’s conduct that colours everything else, and it is raised at every subsequent stage.

Scope, sensibly

Preservation is not an instruction to keep everything forever. Over-broad holds that freeze the entire business are unsustainable and tend to be abandoned, which is worse than a narrower hold that is actually followed. Identify the custodians and categories that matter, and be able to explain the reasoning.

The short version

Decide the trigger date early and defensibly. Issue a specific written notice. Suspend the automated deletion — that is the step that actually preserves anything. Document what you did. Revisit it as the dispute develops.