Home · Guides · updated 3 September 2026

Preserving a conversation before it becomes evidence

Almost everything that goes wrong with chat evidence has gone wrong before anyone thinks about a certificate. The conversation lives on a phone that keeps changing, and the phone is not on anybody’s side.

What is being lost while you decide

A conversation is not a document sitting still. It is the state of an application that changes daily, and several perfectly ordinary things remove parts of it for good:

• Disappearing messages. Where the timer is on, messages are removed on schedule. An export taken afterwards cannot recover them, and neither can the other participant’s phone.
• Delete for everyone. The sender can remove a message from both sides. A placeholder remains where it stood; the text does not.
• Clearing media to free space. The storage tools that reclaim room delete the attachment files. The transcript entries survive, and a later export reads media omitted at every one of them.
• Changing handset. A restore moves a great deal, but not reliably everything, and it overwrites whatever is on the new device. A conversation that was intact on the old phone can be thinner on the new one.
• Reinstalling, or a factory reset. Both are ordinary troubleshooting steps, and both can end the record.
• Moving the account to a new number, which also changes the identifier the certificate has to describe.
• Plain attrition. Media never downloaded, cache expiry, an old handset in a drawer with a flat battery.

Do this today

1. Turn the disappearing-messages timer off for that conversation, so nothing further is lost while the filing is prepared.
2. Take an export with media, following how to export a chat for court. Not screenshots, and not a backup.
3. Hash it and write the value down with the algorithm named and the date it was taken. A hash recorded at the moment of production is worth more than one computed a fortnight later.
4. Keep two copies in different places, and read from a third. The certified file is never the one you open.
5. Write down the particulars while you still remember them: which handset, which account and number, who held it, when the export was taken and by what steps.

That much takes ten minutes, costs nothing, and is the difference between a record and a recollection. The certificate can be settled later; the export cannot be taken later.

Preserve the handset, not only the file

The export is a copy. The device is the source, and where authenticity is genuinely disputed it is the source that gets examined. A phone that has been sold, wiped, traded in or handed back corroborates nothing.

• Keep the handset if you reasonably can, even after moving to a new one. It does not have to stay in use.
• Do not reset it, and do not let it be reset for you while something unrelated is being fixed.
• If the device is likely to be examined, stop using that conversation on it.

Do not tidy the conversation

The instinct to delete one’s own intemperate messages before producing a chat is common, and it is a serious mistake. Deletions are visible: placeholders sit in the sequence, numbered and dated, and an opponent who establishes that the record was curated will make far more of that than the deleted messages were ever worth. Deleted messages explains what an export does and does not show about them.

The same applies to producing an extract instead of a range. Selective production is not preservation, and a record that includes the passages against you is the one that carries weight.

What preserving cannot do

An early export fixes the record from the moment it was taken. It does not establish who was holding the phone, it does not prove that the conversation happened as the transcript reads, and it does not reach anything held on WhatsApp’s own systems. The limits of a WhatsApp export is worth reading before a case is built on one, and admissibility, proof and weight separates the three questions that get run together here.

When the conversation is on someone else’s device

You cannot preserve what you do not hold, and helping yourself to another person’s handset creates a second problem rather than solving the first. The route is procedural: an application to the court for production or discovery, in criminal proceedings a direction to produce, and in either case a request made early enough that there is still something to produce.

Where the device belongs to a spouse or an employer, how the messages were obtained becomes a live issue in itself — see divorce and matrimonial proceedings, where the question arises most often.

Section63 hashes your export in the browser before anything else happens to it and builds the exhibit around that value, so the file you preserve today is the file the certificate describes whenever you come to file it.

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This guide explains procedure and states the law as we understand it. It is not legal advice, and Aarohan Enterprises is not a law firm. Whether a court admits a particular record, and what weight it gives it, is for that court to decide. Have an advocate settle anything you intend to file.