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Email services are now very inconsistent in how they approach undeliverable or "bounce" messages. We'll look at why, and what you can count on.

My question is this: Does Hotmail send an "undeliverable" message to the sender if I send an email to another Hotmail account which is inactive due to the "30 days of inactivity"?

One of the casualties in the war on spam is the "message undeliverable" message that you might get back in response to an email that ... well ... couldn't be delivered.

I say casualty, because you simply can't count on it any more.

I'll look at your specific scenario and then I'll delve into why you can't count on bounce messages any more.

Most free email providers, Hotmail included, will eventually delete accounts that haven't been used in "a while". Exactly how they treat email sent to that account would depend on just where in that "while" they are.

  • Within 'X' days of the last login or use: the account remains active. X might be as little as 30 days, or much, much more. It might also change as mail services adjust their capacity to meet demand.

  • After 'X' days but before 'Y' days after the last login or use: the account is "suspended" for inactivity. Typically, that means the contents of the account - all email and address book entries - are permanently deleted, but the account can still be recovered by logging in. The data would be lost, but the account would still be yours. For example, after 30 days of inactivity your messages and contacts would be deleted, but you might still have another 90 days to get the account and email address back. (Note: I'm making these numbers up!)

  • After 'Y' days but before 'Z' days after the last login or use: the account is deleted. At this point it cannot be recovered.

  • After 'Z' days after the last login or use: the account name is returned to the pool of available account names. A new account can be opened using the original, expired, account name. Note that this is not a reopen of the old account, this is a completely new account with no relationship to the old, other than the account name and/or email address.

"You can no longer count on a bounce message to tell you that there's been a failure."

As I mentioned, 'X', 'Y' and 'Z' are numbers that are determined by the specific email provider, and could be short or long, and could change without notice.

Now, your question boils down to where, in that process, do they start sending bounce messages?

As long as the account is active, there should be no bounces.

While the account is "suspended" for inactivity, there's no way to know. It's up to the email provider and they typically don't detail whether they do or not. I would hope that if email is not going to be delivered into the account's inbox that it would be rejected with a bounce, but as we'll see in a moment, that's not always the case.

After the account is deleted, once again I would hope that it would be rejected with a bounce, but it might not be.

As you can see - the answer boils down to "maybe, maybe not".

So why are bounce messages so unreliable? Why can't you count on them?

Ultimately, we get to blame spam.

Bounce messages are often not sent at all, to prevent spam, and bounce messages are often filtered as spam.

Spammers send a ton of email to email addresses that don't actually exist. They just start "guessing" email addresses made up of likely names and words and whatnot, and if even a tiny fraction are real email addresses the fact that the vast majority go nowhere makes no difference to the spammer. It costs them nothing to send email to bad addresses, and the few that end up being real make up for it.

So, imagine that you're a large email service like Hotmail or GMail or Yahoo, and you're getting millions and millions and millions of emails every day to accounts that don't exist. The vast majority are from spammers, while only a very few are from people who've perhaps mistyped an email address. Do you respond by flooding the internet with millions and millions of bounce messages that, themselves, may go nowhere?

Probably not.

Hence, some of those legitimate mistakes will also result in no bounce message. At all. Those emails just disappear.

There's another approach that spammers use as well that actually uses bounce messages to get their message sent.

A spammer might send an email to "", but also spoof the "From:" address to be "". That means that if "foo" rejects the message with a bounce "bar" will get the bounce message.

Remember that the goal of a spammer is to get a real person to actually read their message. If you get a bounce message, don't you look at what it was that failed in case it was a message you intended to get out? If that's a 'fake' bounce, then the spammer just got you to look at his message.

And by now we've all gotten bounce messages to email we didn't send.

Spam filters are aware of this technique, and as a result are looking at bounce messages that much more closely. The bottom line is that legitimate bounce messages might well be getting filtered along with spam.

If you send an email and get no reply - no reply from the recipient and no bounce message from the email system - that tells you exactly nothing. It may have been delivered and read, it may have been lost completely; there's no way to know.

You can no longer count on a bounce message to tell you that there's been a failure. The failure may occur quite silently.

Article C3529 - October 12, 2008 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

August 21, 2009 5:25 PM

can i return back my delete message and also i send an email can i return this also

October 25, 2011 4:25 PM

LOVE the "Foo" and the "Bar". Wonder how many people got it? Thanks for everything you do!

November 22, 2011 1:25 PM

Why is is when i send an email to a hotmail account I have been told is closed do I not get a 'mail undeliverable message' in response? Could it be the account is still open?

You are never guaranteed to get a bounce message - for any error. Often systems will simply not send them for various spam-related reasons.
November 22, 2011 1:37 PM

Hotmail accounts aren't that easy to close. The account could be in a waiting period. In fact, there are a hundred other reasons that an deliverable message doesn't get back to you, including the various spam blockers you may have on your account, or that Hotmail just didn't want to send one. So not receiving an undelivered message is not "Proof" that the account isn't really closed.

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