Re: Retrieving only new mail

I just made an experiment. I tried the same thing with Mozilla
Thunderbird. You know what? It doesn't suffer from this problem!! It
doesn't re-download the messages which are already in its inbox!

pacikk wrote:
Hi Sam,
thanks for you reply! Your Unique-ID explanation got me thinking and
searching on the net and what I understood up till now is that the
server generates a unique ID for each and every email which persists
across sessions and which is apparently stored in the header of the
email. Upon clicking on the Options of an email downloaded in Outlook
one can easily find this message-ID in the email header.

I found this information at:
http://www.freesoft.org/CIE/RFC/1725/7.htm
The unique-id of a message is an arbitrary server-determined
string, consisting of characters in the range 0x21 to 0x7E,
which uniquely identifies a message within a maildrop and
which persists across sessions. The server should never reuse
an unique-id in a given maildrop, for as long as the entity
using the unique-id exists.

So to me it seems that Outlook doesn't check the message-IDs of the
email headers (of some old .pst file) which you import from some other
machine or if you happen to reinstall outlook and want your emails
back. Outlook just stubbornly downloads all the emails again. Hope
somebody comes up with a solution!

Patrick


Sam wrote:
pacikk writes:

Hello,
My question is related to popping mail from Yahoo with the option
'Leave a copy of the messages on the server' enabled.

I'm wondering whether there is some Outlook configuration file which
keeps track of which emails have already been popped. The setup works
fine with only the new emails being downloaded. But problems arise if
for e.g. I decide to transfer my .pst file with all the already
downloaded emails to a new machine and setup outlook to point to this
.pst file. Once I hit the Send/Receive button all the mails I have
stored on my Yahoo account start to download again, ending up with
1000+ duplicate emails.

Is there some switch which tells outlook to download only unread emails
or to download emails after a certain date? Somehow this function is
already in place, because otherwise with the option of leaving the
messages on the server each time outlook check for new email it would
try to download all the server messages each time.

It's not done using dates. POP3 servers maintain and generate a unique
identifier for each message in the mailbox. Mail clients, such as your
Outlook, keep their own copy of the downloaded message's unique IDs. When
the mail client checks for new mail, it compares the unique ID of messages
in the POP3 server with the list of unique IDs of messages it already
downloaded. That's how it knows which messages are new and need to be
downloaded.

When you configure the same account on another computer, the second Outlook
will obviously have no record of unique identifiers that have been
downloaded already by the first Outlook, so it sees everything in the POP3
account as new mail.

The .pst file that you copied is just a folder that contains message text.
It does not contain the unique identifiers of those messages on the POP3
server.

There's probably a separate configuration file, or a registry entry that
holds your POP3 server's hostname, login, password, and a list of unique IDs
that have been downloaded.




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