How can I prove an email was actually sent to me?

June 14th, 2017

Someone claims to have sent you an email message. You never got it, as far as you know. How can you prove an email was actually sent? How can you check?

how to prove an email was sent

Proving that an email was sent

As the purported recipient of an email message, the absolute best and most straightforward way to prove that a message was sent to you is to have a copy of that message. I.e., this could be:

  1. A copy in your inbox or another email folder
  2. A copy in your permanent Email Archives

If you have a copy of the message, you are usually not trying to determine if the sender sent it. If you are, you need a forensic analysis of the email headers (particularly the Received lines, DKIM signatures, etc.) and possibly get the sender’s email provider involved to corroborate the evidence. How this would be done is beyond the scope of this particular article. Instead, we focus on the more common case — you, the recipient, do not have the message the sender claims they sent to you. What do you do?

What happened to the email?

In reality, there are only a few things that could have happened:

  1. The recipient never actually sent the message
  2. The recipient did send the message, but it never actually made it to you
  3. The message did make it to you, but maybe it got accidentally or inadvertently deleted (or overlooked)

We discuss many of these possibilities in the article: The case of the missing or disappearing email messages. Let’s work backward with what you may be able to check and investigate. Start your search soon. The more time that elapses, the less evidence you may have as logs and backups get deleted over time.

Maybe the email was accidentally or inadvertently deleted or overlooked?

First, you should know that the sender could have put tracking on the message so that they were informed if you opened or read it (even if you are unaware of the tracking). In such cases, the sender can disprove false claims of “I didn’t get it!” See: Has your email been seen? Read Receipts and Web Bugs.

If you never saw the message, start by searching all of your email folders for it. Maybe it was accidentally moved to the wrong folder or sent to the “Trash” folder. If you have a folder that keeps copies of all inbound emails (like LuxSci’s “BACKUP” folder), check there too. Check your spam folder and spam-filtering system. Your spam-filtering system may also have logs that you can search for evidence of this message passing through it. Finally, check any custom email filters you may have set up with your email service provider or in your email programs. If you have filters that auto-delete or auto-reject some messages, see if that may have happened to the message in question.

The searches above are straightforward, and you can do many of them yourself. Often, they will yield evidence of the missing message or turn up reasons why you might not have received it.

Maybe the email was sent but didn’t make it to you?

Email messages leave a trail as they travel from the sender to the recipient. This trail is visible in the “Received” email headers of the message (if you have it) and in the server logs at the sender’s email provider and your email provider. If you know some aspects of the message in question (i.e., the subject, sender, recipient, and date/time sent), you can ask your email service provider to search their logs to see if there is any evidence of such a message arriving in their systems. This will tell you if such a message made it to your email provider; however, email providers can typically only search the most recent one to two weeks of logs. So, if the message in question was from a while ago, your email service provider may not be able to help you (or may need to charge you a lot of money to manually extract and search archived log files if they have them).

If your email provider does not have any record of the message or can not search their logs, you (or the sender) can ask the same question of the sender’s email provider. If they can provide records of such an email being sent through their system, that will prove the email was sent.

The log file analysis provided by the email providers could also explain why you didn’t get the message. I.e., your email address might have been spelled wrong, there could have been a server glitch or issue, etc. However, if the message was sent long ago, the chances of learning anything useful from the email providers are small. Also, if you use a commodity email provider such as AOL, Yahoo, Outlook, Gmail, etc., you may find it difficult or impossible to contact a technical support person and have them perform an accurate and helpful log search. More premium providers, like, do this kind of thing as a matter of course.

The last thing you can do is have the sender look in their sent email folders for a copy of that message. If they have it, that can indicate that they sent it and can also be used to see why you didn’t get it (i.e., wrong email address, content that would have triggered your filters, etc.). However, be wary. It can be easy to forge a message in a sent email folder, so I would not recommend using that as court-worthy evidence that the message was actually sent. And, even so, it does not prove that it ever made it to your email provider or your inbox.

The recipient never actually sent the email message

How can you prove an email was sent if the message was never actually sent, but the sender claims it was? If this purported sending event was recent, then the data from your email service provider can prove that it never made it to you, but that doesn’t prove that it was not sent. The sender may claim that they do not have a record of sent messages and that their email provider will not do log searching, and that may also be true. At this point, you are stuck without a resolution.

While email is a reliable delivery system, there are many ways for messages not to make it to the intended recipient. Whether it was not sent or was sent and never arrived, the result is the same- no message for you. I would ask your lawyer, but I would suspect that sending an email message without any definitive confirmation that it was received would not be a legally binding form of notice. However, that may also depend on the details of any contracts between you and the sender.