Multiple Copies of Emails

Alan -- I'm with you. I've done nothing (waiting for a fix from Apple) and the random duplicate email problem as gone away for the last week or so. By all means, I don't believe the problem has been fixed in any way. Like with the disappearing passwords, the randomness of it makes it difficult to troubleshoot and I suspect it will come back until Apple dedicates the resources to solve the issue(s).

Just had another thought that might be worth "eliminating from our enquiries":

Did people do a clean install of Snow Leopard, or an upgrade from Leopard? Personally I did an upgrade on both my Mac Pro and my MacBook. Brand new MBP with SL arriving tomorrow though 🙂 , so we'll see if that does the same...

Yesterday I had the most extreme example so far; 62 copies of every email on the POP servers re-downloaded. What a mess.

To those who keep saying that the problem is solved because it hasn't happened to them in a few days - THIS IS A RANDOM PROBLEM! I've had it go for nearly two weeks without occurring, and then occur 10 separate times in the same day. I put NO value in hearing that the problem has gone away unless it does so for a month or more.

I think there's a corollary to Murphy's Law that says "Problems that go away by themselves can come back by themselves" and it certainly applies to this one.

I did a clean install and the problem was still there.

Hello
I had similar problem since a few weks so, before I installe Snowleopard and I think I fix this problem now.
I delete all my rules and it disappears.
I think there was a "loop" in my rules.
All is good since yesterday. I hope it will stay as this.
Hope this will help

Update: Ernie's suggested fix did not fix the problem. I thought it did since the problem hasn't popped up for a number of days, when before it was occurring more frequently.

So once again, Mail starts breaking with repeated:
Seen Messages: error "%{PROPERTY}@ is a required value." in -[SeenMessagesManager saveChanges]

and then repeated:
Seen Messages: error "The file “MessageUidsAlreadyDownloaded3” couldn’t be opened." in -[SeenMessagesManager _accountForAccountID:]

with repeated interleaved:
Seen Messages: error "The file “MessageUidsAlreadyDownloaded3” couldn’t be opened." in -[SeenMessagesManager saveChanges]

I've filed reported bugs about this issue to Apple. I'm a patient fellow and like to fix things myself, but itt's escalated to the point where I'm now contacting Apple support.

I am having the same problem in Snow Leopard. It seems to only happen in Snow Leopard. Duplicates of thousands of emails download in my pop account inboxes.

Having encountered this problem, I tried the earlier proposed remedies, had no luck. Then, suddenly, the multiple downloads stopped for about a week. Just as inexplicably, they started again. Tried running Mail in 32 bit mode, and the download happened again within a couple of hours. Doesn't look like that's the solution.

I have been having this problem for over a month and am getting very frustrated waiting for Apple to solve this problem. I also believe it is a time machine issue. As I was sitting here working time machine started to run so I waited and sure enough mail redownloaded 51 emails I received.

Is there any light at the end of this tunnel????? I have tried most of the fixes in this thread and have had NO luck.

Heidi

I have a tendency to believe that the duplicate emails and the password rejected issue are linked. It seems that the password rejected issue only happens when there is high traffic on the pop server or ISP (read slow connection). I've also had the password rejected issue when time machine is sucking LAN bandwidth. It appears that if mail doesn't get a response from the pop server it assumes the password was rejected (even though the password is correct).

I've notice a similar issue with duplicate emails. I only seem to get them during high traffic times (such as during work week, work hours or when LAN is busy with time machine backups). I'm wondering if there is a similar acknowledgment problem which is causing mail to default to downloading all mail since the mail server acknowledgment wasn't received in the specified time.

These both may be related to a timing issue and how mail handles slow responses from the mail server(s). Or, I could just be blowing wind.

I think I've got it figured out - at least for me. When I excluded the 'MessageUidsAlreadyDownloaded3' file from the Time Machine backup, the duplicate problem went away (for now) I will re-post if it recurs. This makes a lot of sense to me now. If Time Machine continuosly backs up the 'changed' files on the Mac, and the 'MessageUidsAlreadyDownloaded3' file is changed every time Mail is checked, it will constantly be getting backed up. During the back-up, the file is locked, so it can't be accessed by the Mail program when it is checking for new mail, so the Mail program simply re-downloads everything and the whole cycle starts over. By excluding the file from the back-up, it will no longer be locked, so Mail will be able to access it.

Gregory that sounds logical - however I wonder why this would not have been an issue in 10.5...

I think this may be the problem but I am waiting for Apple to have a fix for it. The reason why I think this makes sense is because I have a laptop and imac both running snow leopard. The laptop I've never used Time Machine on and I don't get this duplicate email problem only the imac which does have time machine configured on it and I get this problem. I think you found the source of the problem!

SKEL--I'll have to agree with you. I've been running time machine with Leopard since it came out and didn't have this problem until Snow Leopard. Why would 10.5.x work perfectly fine with time machine and Snow Leopard have issues. I wish it were that simple but i suspect it's not. I mean, even if it were true the file is like 45K which should take a fraction of a second to backup and release the lock on the file. The mail app should be able to wait a fraction of a second for time machine to backup a 45K file and release a lock so it can write to it. I guess we'll see; here's keeping my fingers crossed.

I also agree with skel. And just to add .. I get the e-mail duplication every single day (and have had since upgrading to SL). I currently have e-mail set to check hourly, and of course Time Machine the same. So for this to be the true explanation, I'd have to have e-mail check and TM backup of one 45k file occurring at the same instant every hour of every day ..

I don't think so ... (Not that I'd blame anyone for trying to identify creative possibilities 🙂 )