Duplicate Email - BIG PROBLEM!

Yes. I too have suddenly begin to have this problem. What is most interesting is that it re-downloads all of the e-mail off the server from the date I installed Snow Leopard. I delete all of the duplicates and they re-appear hours later, all from the date Snow Leopard was installed. Very interesting. But annoying. Surely there must be a fix here.

Same problem as well. Takes so long to delete hundreds of read e-mail, just to have them reappear - my wife is going to kill me for updating to Snow Leopard so soon. 😟

Another me too. Happened in my wife's account last night, and mine has just redownloaded about 80 emails for me.

So I guess it looks like a Mail / SL issue, rather than one with our ISPs.

OK same here. I thought it was an issue with iPhone as I've just started using one at the same time as u/g to SL. Sort of pleased that it's a SL issue but hope Apple sends a fix soon. Getting to be a real pain deleting all those duplicates, happened four times now since installing SL.

Those having this problem, please use the Finder to open Home/Library/Mail and locate the file named MessageUidsAlreadyDownloaded3. Use Get Info to see when this file was last updated -- should be after the last time new messages were downloaded?

Quitting Mail and removing this file, and then relaunching Mail will result in a freshening of the file, if it has become corrupted, but will once more download everything still on the server. But hopefully for the last time. This has solved this problem for others, as has been reported in an earlier topic at:

http://discussions.apple.com/message.jspa?messageID=10073157#10073157

The discussion goes into other dimensions of the problem for some people checking mail from more than one computer or device, and some providers might be more prone to have this reoccur.

Ernie

My problem is slightly different. Messages delivered to my Exchange account appear twice in the In box. Not POP. If one is read or moved, the second, "ghost" message disappears when opened. No amount of cache rebuilding and setting changes has fixed this. Other accounts - POP and IMAP - work normally.
I anyone else experiencing this?

well, I have followed the route given finder - library - mail and have checked in every file and cannot locate MessageUidsAlreadyDownloaded3 to delete it???

Do you have a POP account? Would have to have at least one POP account to need that file.

If using a POP, then in the Finder, did you click on the icon of a house and you name to open your Home folder, and then look in the Library of the Home folder?

Ernie

I have six pop accounts. This file is nowhere on my computer except the history file cache of this thread. I also have a Mobile Me account which behaves identically. ALL of my previously downloaded emails download from the date I installed Snow Leopard (and not before).

Ernie Stamper wrote: "Do you have a POP account? Would have to have at least one POP account to need that file."

Thanks for this forum topic. After upgrading to SL on August 31, I had my THIRD Kernel Panic (aka, Gray Screen of Death) on Tuesday, September 8. After that, my e-mail developed this "duplicate" issue on all of my POP3 accounts. This resulted in hundreds of e-mails.

The recommendation on going to Home/Library/Mail and deleting the "MessageUidsAlreadyDownloaded3" file worked for me! Thanks!

Hey all,

I'm glad I'm not the only one experiencing this bug. It is driving me CRAZY. I've used Mail for six years and now I spend hours a day deleting duplicate emails. I hope Apple fixes this in 10.6.1, soon.

Here's a potential clue: I have deleted MessageAlreadyDownloaded3 twice and both times I had several hours when the bug did not occur. I was also using different networks than my home network. When I returned to my home network, the bug started happening again. So either there is something specific to my network that causes this (my ISP is Time Warner and my router is a Time Capsule), or there is simply a window for how long deleting MessageAlreadyDownloaded3 will solve the problem.

For the record, this is happening all ALL of my seven my accounts (including IMAP, though most are POP) and only one of them is checked by another client (an iPhone).

This is a truly annoying bug. Please fix, Apple!

I'm seeing the same thing since SL, with my only account, which is POP. I just deleted MessageAlreadyDownloaded3, and now mail is "stuck" with a spinning wheel next to my Sent folder, and four messages going nowhere in my Outbox. I like to think that mail is rebuilding something and it will clear up in a while (I've got 15K messages in my inbox, but I've already emptied my POP server), but time will tell.

For those looking to clean-up duplicates, I used this one of the scripts from here: http://homepage.mac.com/aamann/Mail_Scripts.html Seemed to do the job, although it doesn't look across folders.

If the duplicates are all in POP accounts then it might be to do with Exchange 2007 and not Snow Leopard. I found a few websites that discussed the duplicate mails for both Macs and PCs using Exchange 2007. For example: http://hms.harvard.edu/hmsit/pg.asp?pn=email_preventduplicates

This happened to me when I installed SL at home. I thought it was a SL issue until I went to work (which still runs Tiger) and I found that the duplicates had arrived there too. When I looked at the duplicate mails in on my Tiger mail - I found that there were very minor differences in the duplicates - eg. in one email the sender was "Bob Brown" while in the second email the sender was "bob.brown@XXX.com" - it is almost as if somehow the mails left on Exchange were recognised with a different code. It seemed rather a coincidence that it all started when I installed SL. So I think that the connection between SL and the Exchange server sparked off that difference in code recognition?? Exchange servers are complex creatures which I don't claim to understand them.

And some people in this thread seem to have had duplicates with IMAP as well and I don't understand that one either.

But I can offer one work around to the multiple emails. If you create a smart mail box with the single criteria that all unread messages go in there. When the duplicates come in you can at least save time and delete the duplicates easily from that smart folder without having to manually identify the duplicate mails.

I have the same problem, so I will try the fix tonight. This is so annoying!