When Evidence Disappears Without Anyone Deciding

Consider a hypothetical Rockford food distributor that delivers a refrigerated load to a grocery chain. Overnight, the trailer’s cooling unit fails and $400,000 of product spoils, and the chain’s general counsel soon sends a short letter saying the company is “evaluating its options.”

Nobody at the distributor destroys anything on purpose. But the fleet vendor replaces the cooling unit and scraps the old one, the trailer’s temperature data overwrites itself after 90 days, and when the dispatcher upgrades her phone, her texts with the driver disappear with the old device.

Six months later, the grocery chain sues. The distributor’s best defense would have been that the cooling unit itself was defective, a theory that would also have supported a claim against the manufacturer. But the unit, the data, and the texts are all gone.

No General Duty, With Large Exceptions

At first glance, Illinois law seems to favor the distributor. In Boyd v. Travelers Insurance Co., 166 Ill. 2d 188 (1995), the Illinois Supreme Court held that there is generally no duty to preserve evidence. A duty arises only through an agreement, a contract, a statute, a special circumstance, or a voluntary undertaking, and only where a reasonable person would have foreseen that the evidence was material to a potential lawsuit.

Later, in Martin v. Keeley & Sons, Inc., 2012 IL 113270, the court declined to expand that test into something close to a general duty. Both decisions, however, address a specific question: when someone else can sue you for negligently losing evidence they needed.

Why That Rule Is Less Comforting Than It Sounds

That focus leaves a gap that matters for most businesses. A company that is itself a party to the dispute, or reasonably expects to become one, faces a different risk: sanctions in its own case. In Shimanovsky v. General Motors Corp., 181 Ill. 2d 112 (1998), the Illinois Supreme Court held that a potential litigant owes a duty to take reasonable measures to preserve relevant and material evidence, a duty courts can enforce through their power to sanction discovery violations.

Those sanctions can include barring the party from offering certain evidence or instructing the jury that the missing evidence would have been unfavorable, and in serious cases they can go further. The distributor in the example, then, may never face a separate spoliation claim. Instead, it may simply lose the ability to prove its own defense.

Federal court applies its own rule to electronic records. Under Federal Rule of Civil Procedure 37(e), if a party fails to take reasonable steps to preserve electronically stored information and it can’t be restored or replaced, the court may order measures to cure the prejudice. If the party acted with intent to deprive the other side of it, the court can presume the information was unfavorable, instruct the jury accordingly, or dismiss the case.

The Evidence That Disappears on Its Own

In practice, most lost evidence is not shredded. Instead, it is replaced, recycled, or overwritten by systems doing exactly what they were set up to do: telematics and sensor data roll over, email retention policies purge old messages, phones are upgraded, vendors repair or discard damaged equipment, and departing employees’ accounts are closed.

Insurance adds another layer of risk. Property policies commonly require the insured to preserve damaged property for inspection, and an insurer that pays a claim may want the evidence to pursue the party responsible, so discarding the failed equipment can complicate both the coverage claim and any later recovery.

AI Systems Erase Their Own Records

AI tools make the problem worse. Prompts, outputs, system logs and configuration settings are often overwritten automatically, sometimes within days, and a vendor’s model update can change how the system behaves overnight. By the time a demand letter arrives, the record of what the system actually did may already be gone.

Courts treat this data like any other evidence. In the copyright litigation against OpenAI, a federal magistrate judge in New York ordered OpenAI in May 2025 to preserve output logs it would otherwise have deleted, including chats users had asked to delete. Automated deletion is not an excuse once litigation is foreseeable.

In an AI dispute, the evidence that matters usually includes:

• Prompts and outputs: the inputs and responses at issue, with timestamps and user identifiers.

• Settings and logs: configuration, system prompts, guardrails, and a record of every change.

• Model and version history: which model was running on which dates.

• What was promised: the contract, specifications, demo recordings and sales materials.

• Internal communications: emails, chats and support tickets about the problem.

A Preservation Letter Works in Both Directions

The simplest protection is a written preservation demand. Sending one to the other side, and to any vendor holding relevant equipment or data, makes it harder for anyone to claim they did not see litigation coming, and it can help establish the foreseeability Illinois courts look for.

The same logic applies in reverse. A letter like the grocery chain’s, vague as it was, is exactly the kind of signal that should prompt a business to suspend routine deletion and secure what matters.

Much of that data may sit with a vendor rather than with the business. A written preservation request that names the accounts and date ranges, and a record of the vendor’s response, can matter later. Internally, a litigation hold that names AI data specifically, a pause on automated deletion, and screenshots of the system’s configuration before anyone fixes it will keep the record intact while the problem is being solved.

Cheap to Preserve, Expensive to Explain

Preserving a failed part, exporting a data log, or imaging a phone costs very little, while explaining to a judge why those things no longer exist can cost the case. The useful question, then, is not whether Illinois imposes a general duty to preserve, but what this particular dispute will require someone to prove.

We help businesses respond to threatened claims, preserve evidence that supports their position, including AI and system data, and evaluate claims against vendors, manufacturers, and insurers. If a dispute is starting, we can help identify what needs to be preserved before routine systems erase it. Contact us to discuss your matter.

This article provides general information and does not constitute legal advice. For guidance concerning a specific matter, see our commercial litigation services. The appropriate steps depend on the dispute, the evidence involved, and the parties’ obligations under contract, statute, and court rules. To discuss potential representation, request a consultation. Submitting an inquiry does not establish an attorney-client relationship.