I have a dispute on my hands in which the other party (landlord's real estate agent) dishonestly claims to not have received an email that I truly did send.

My questions is, what are the ways to prove that the email was indeed sent?

Thus far, the methods that I have already thought of are:

  • Screenshot of the mail in the outbox
  • Forwarding a copy of the original email

I am aware of other things like HTTP/ SMTP headers etc that would exist as well.

  • Are these useful for my purposes, and if so how do I extract these?

The email in question was sent using Yahoo webmail ( http://au.mail.yahoo.com/ ).

Edit: I am not seeking legal advice here, just technical advice as to how to gather this information.

  • 1
    at best you can prove that a mail was delivered between your mailserver and his mailserver.
    – artifex
    Commented Jan 21, 2010 at 11:04
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    Great information, however, even if it is in your 'Sent Mail' that is not proof it was delivered. You could get a failed delivery notification you subsequently deleted. I think that by retaining it in your sent mail and tracking the actual email address delivery was attempted may be sufficient proof. Please consult with counsel before attempting, your local laws may vary.
    – user44651
    Commented Jul 30, 2010 at 18:50

12 Answers 12


Most people are shocked to hear this, but email is not actually guaranteed to ever reach the intended destination.

It might fail for a variety of reasons. It could simply fail to arrive (for several reasons) or could be getting redirected to the recipients spam folder for some reason. If you think an email hasn't been delivered, you should send it again. I usually forward the original so that recipient knows I've been trying.

You can turn on “read receipt” or “return receipt”, which will send an email back to you automatically, but this feature is often disabled by recipients because it has been so often abused by spammers in the past.

Will covered just about everything else in his answer.

  • 12
    I once tried to send 5000 e-mails to my gmail address using my ISP's SMTP server and only 4984 arrived... That 16 e-mail just silently disappeared... Commented Dec 1, 2009 at 5:46
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    I don't know about others but I consider requesting read/return receipts a rude practice and would never send them back or use an MUA that sends them by default. Commented Nov 26, 2012 at 14:54

There is nothing 100% that you can use to prove on your own.

If you had your own mail server, you can show outgoing logs - however, they can be falsified.

You can use read receipts, but again, they can be falsified.

The best bet is if you use a third party mail server that is impartial, and they can provide logs, that should stand as proof.

You may have luck if you email Yahoo (and say you are willing to pay for their time on the matter) and try to get a log / proof that an email was sent on a time/date.

I am not sure you can force them in to this unless the place you need it for are involved in a criminal matter... It may work for civil, but you would need a court order.

Failing this, if it is in your outbox with a time and date, this is hard/impossible to fake on a web based email server (just check that changing your date/time and sending doesn't fake this). Then, print out and if you need to go to court, you could always have a laptop, 3g stick and projector and prove that it was sent... but again, only if it can be prooved that you can't fake this.

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    I wouldn't go into too much detail here on trying to find 'proof' an email was sent. Any digitally encoded text can be faked and email is fundamentally a text protocol. Commented Nov 30, 2009 at 23:27
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    Can be faked unless cryptographycally signed I guess.
    – vtest
    Commented Nov 21, 2011 at 8:58
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    @vtest: For proof of transmission you would need a cryptographically signed transmission receipt from an independent SMTP server. Existing SMTP servers (of the sort used by Yahoo) do not provide such receipts, so far as I know. Commented Nov 29, 2011 at 17:07

Unfortunately, as with physical letters, proof of sending is not proof of receipt.

While the e-mail shows as sent in your mail client and it will probably be shown as sent in your ISPs mail server, there will be (many) other mail servers between there and the final recipient. At each one of these the e-mail could have got lost or delayed, so it could well be that your landlord's estate agent is telling the truth (though I'll admit it's more likely that they are lying).

To have proof of receipt you'll need the equivalent of registered post here in the UK where the recipient has to sign for the letter.


There is a website called readnotify.com that will confirm if you have sent an email and that it will tell you if the email was opened or not. As an example, suppose you register your email [email protected] with readnotify.com, ok, then if you were to send an email to [email protected] via readnotify.com, you can append at the end of the email address in the To field [email protected]. The email gets routed through the readnotify server and with a webpage that you use to sign on to readnotify.com using your registered email address (i.e. [email protected]) with your chosen password, you can then view that the email was sent and the time it was opened by [email protected].

Initially I was sceptical of it as there is no known method or proof that the email was actually sent for a number of reasons such as the route to the intended recipient was down, an incorrect email address was used by accident (it happens to all of us, leave out a vital letter of the email in a hurry and fully convinced that we sent it!) and returns back bounced saying the email address does not exist, a mailserver fell off the internet, dns errors, even a cut in the internet pipe to the destination country or even your email address is marked as junk/spam...the list goes on...to sum, no way of telling..apart from having a sent folder in your email client such as Outlook, Thunderbird etc...

But somehow, readnotify does seem to work. Just don't ask me how it does it, it apparently puts a trace on the email and when the intended recipient opens it, somehow readnotify receives some message to say the email was opened and for how long etc...scary though to think that it does work but that's my opinion.

The long and short way of doing it is to get the ISP of both parties to bend over to send you a record to say that the email was sent..check with your local laws etc as I am sure you would have something in accordance to the data protection act (if a such thing exists in your country)...

  • Nice answer. Do you know if readnotify.com works even if the recipient has receipts turned off? Commented Dec 1, 2009 at 0:36
  • Yes, it does not use receipts apparently...!!! All I know is it just works...
    – t0mm13b
    Commented Dec 1, 2009 at 0:48
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    See: securityfocus.com/columnists/258
    – NVRAM
    Commented Dec 1, 2009 at 1:10
  • 1
    @NVRAM - good article - it does depend on HTML mail, and frankly I don't know how prevalent that is. I'm mostly a ascii-email person myself. Commented Dec 1, 2009 at 15:11

Well, it's not really a way to prove that the email was sent, but I sometimes like to BCC myself (maybe even to an alternate email account) to see that the email server did something with that important email.


You could try contacting the real estate agent's ISP and ask them to provide logs. If the logs show your email, then, you proved you sent it to the agent. Of course, the agent can still claim to have not received your email.


I can't help you with this particular case, much more than the others did that replied to your post, but I have a good suggestion for the future.

You can use copyconfirm.com.

It's an easy tool that exactly solves this problem. You can easily prove what you sent, when you sent it and to whom. I use a private account so it costs you nothing (if you don't use it too much..)


There is a new service (that I'm affiliated with) called The Evidence. Basically you append a wildcard to the recipients email address called an eEvid.

For example, if you were sending the email to [email protected], you would actually send it to [email protected]. When the email gets to John Smith there is no indication that the email has been tracked (John Smith doesn't know) and neither does it ask John Smith to do anything. He is completely unaware of the fact the email has been certified. As the sender of the email you are immediately provided with a Certification of Proof (by email).

It's free for a limited use account.


The only way is to turn "Read receipts" on. In Outlook you do that by going to menu Tools -> Options -> Preferences -> E-mail options -> Tracking options -> check "Read receipts"

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But even then, the recipients can choose to ignore the receipt and refuse to send it... If they do however click "OK" on the "Send receipt" dialog they get, you will have proof that they read it...


If you wanted to go that level, have your legal representative subpoena the recepient's ISP's logs and their computer. Have a forensics specialist go through them. That "may" show receipt. Short of that, email is a "best effort" protocol and does not guarantee delivery. There are some ways to show you may have attempted to send, but short of examining the receiving systems, no other way to prove receipt that I'm aware of.

You also should consult with someone in legal where you live. If I'm not mistaken, there was case law stating proof of attempt to send a payment is still useless. There were cases where people mailed payments and the letters were lost. They managed to get the postal system to verify that the letter got lost during transit, but the ruling went against them since the realty company had no way of knowing and no expectation that they had a duty to wait any more time due to a third party's failure.

As always, get good legal advice.


Send your emails through eevid.com, a freemium service that will deliver your email to the intended recipient and send you back a digitally signed PDF file that proves its contents and delivery. In seconds and without the recipient's intervention.


Readnotify.com embeds a remotely hosted invisible image within your email body. The image name's is uniquely codified, allowing the server to know that a particular email has been opened. This technique, also used by spammers, obviously raises privacy considerations; furthermore, many email clients, such as Outlook, are defaulted to block remote content from loading due to security reasons.

Copyconfirm.com is pretty good on proving the contents of the email they receive through "Cc", but provide no information on whether the email also reached the "To" recipient.

Eevid.com does the job nicely, as it proves both the email contents and its delivery to the recipient mail server. What I find particularly attractive from their approach is that is solely based on Internet standards, already accepted worldwide, making a quite strong evidence.

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