When user performs Send and Receive, e-mail messages on the server are downloaded again rather than ignored.
User has Outlook leaving messages on server for n days and deleting when trashed.
The Microsoft Help and Support page says:
Outlook Downloads Messages from a POP3 Server Twice Outlook downloads messages from a Post Office Protocol 3 (POP3) server again after it empties the Deleted Items folder even if you have both the Leave a copy of messages on the server and the Remove from server when deleted from Deleted Items options enabled on the POP3 account.
There is not an available work-around for this problem. . . Simply delete the duplicate messages.
Yes, that's very helpful. Let's see if we can improve on that just a wee bit . . .
As the Microsoft note would indicate, there is not easy one fix for this. Otherwise, the Help and Support note would probably have been more, well, helpful.
There is no easy solution for this POP3 issue because there are so many causes. However, we do have a list we've compiled, please check the following:
Only a Specific Message:
If it is only one or two messages and not all, check the web mail. You'll probably find that/those messages still bold/unread. Mark the message(s) read and try again.
Sending/Receiving Too Often:
If you have a lot of new mail, you don't want to kick off another send and receive when the current one is still going. Change the "Schedule an Automatic Send/Receive every n minutes" setting to a larger value and try again.
Two profiles were setup for same account (for different sending e-mail addresses). While first profile was downloading mail, the second one was doing it, too. Result was the marking of read on the server was completely hosed and duplicates were being created in the client.
User reported this issue after adding AVG. Adding the free AVG tags seems to have caused downloaded messages to be different enough for Outlook to download all e-mail again.
Mail Rule/Forward On:
A local mail rule forwarded mail back to the server. This showed up by the server actually having duplicates. The clue was the mail header didn't show the normal incoming mail header but the user's Outlook client.
Mail Rule/Move a Copy:
If you don't receive all messages again, but only ones you filed, then you probably have a mail rule that auto files for you, using the "move a copy ...". Change the rule to "move this message" instead.
Messages Before a Certain Message Downloaded Repeatedly:
If the Outlook drops the connection (red x) during a Send/Receive it will download all mail through the drop again. It doesn't seem to delete server side mail until the transfer is complete. The dropped connection could be network related or the base64 MIME 0x10CR character issue -- a bad e-mail body. If the issue is a bad e-mail read the e-mail in web mail and then delete it.
All messages after a certain message are downloaded repeatedly:
This occurs when Outlook has downloaded all messages but then cannot tag this message as "read" so it won't be downloaded again. The tagging "crashes" and cannot continue. So every sync brings down all messages after "this" message. Solution is to read message, respond to it, and then delete the message in the in-box, which should also delete it on the server. It not explicitly delete the message via the user's web mail.
Still broken? Maybe do only as last resort . . .
Export mail, backup bookmarks, the user's contacts, and other personal data. BUT NOT THE OUTLOOK PST. Create another O/S user account and delete the current one. Import the mail from the backup. Details:
1. In Outlook, turn off auto send and receive, empty junk. Highlight all personal folders on the left and then click File--> Import/Export --> Export file --> Give name, select PST or Personal folders type, and note where you are saving it. If it asks about sub folders, confirm that you want them copied, too.
2. Back up contacts, the saved/exported mail, bookmarks and any other personal data from My Documents and the Desktop.
Alternately, you can change this O/S user to turn sharing on. Just make sure that the other users can "change your files". The paths between users is:
XP - C:\Documents and Settings\<username>
Vista/7 - C:\Users\<username>
You can copy the Application Data folder except for the buried Outlook folder. You can get the Contacts though.
3. Create a new user account. (Make sure that at least one is an administrator account after the original is killed.)
Start --> Control Panel --> Users.
4. Log out and Log in as the new user. Wait for the O/S to do the first login setup.
5. Transfer all your data to the new account that you backed up or shared in step 2.
6. Start Outlook. Import the backup file from step 1. Verify contacts exist.
Run with your new identity for a while. After a while, delete the original user after you are sure nothing was accidentally left.
You can switch the user to IMAP instead. That way the user is always working off the server copy instead of a local PST and synching. All clients should access with the same protocol (e.g. IMAP vs POP).
IMAP is can be better because local client backups for mail aren't as important. Also, you don't have to worry about one mail client/device downloading mail accidentally before the other client(s) can also download it. It also doesn't seem to suffer from the read/not read issue as much, nor the "bad" e-mail problem that afflicts the Outlook client using POP.
However, as IMAP works on the server and obviously then leaves messages on the server until deleted, the mail file can get really large. Watch for hitting quotas when using IMAP. Some mail clients and query and post in the mail client the quota percentage (usually as a line/bar) for the user's convenience. It also cannot inherently go offline, the mail client software would still have to make/keep up a local copy of mail if this is desired.
If this is a Domino server, use the Notes Client if possible. It doesn't suffer these problems and it's communication with Mindwatering's Domino servers is more secure via all traffic being encrypted and robust than using Outlook. Also, with Notes 8.x, the client experience is greatly improved and pretty equivalent again with Outlook. (Outlook 95's interface was basically a copy of the Notes R5 one. Unfortunately, IBM worked on back-end and developer/web improvements over the next couple releases and ignored the Notes mail experience. They circled back in R8 in a great way for a new heavily customizable mail and applications interface.)