Messages repeatedly downloaded with outlook.office365.com

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studiosus
Posts: 5
Joined: June 24th, 2014, 9:20 am
Location: Estonia

Messages repeatedly downloaded with outlook.office365.com

Post by studiosus »

After migrating work e-mail account to outlook.office365.com (IMAP) few months ago, the messages in the various subfolders in this account are repeatedly downloaded - even after they have been already downloaded before (in all folders I have checked the "Select this folder for offline use"). I have used TB for the last 15+ years and never encountered this kind of issue. I have also used several other and different accounts with different IMAP servers, but this is something new. Not all folders in this account behave the same way and not every day, but I would say once a week or so the messages in my most frequently used IMAP folders are downloaded again (the moment I click on the folder, it goes empty and then the message download process starts).

Can this be something related to outlook.office365.com? Is there a way to check the reasons why the folders are synchronized again and again? Using the latest version of TB with a few add-ons (Lightning etc).
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tanstaafl
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Joined: July 30th, 2003, 5:06 pm

Re: Messages repeatedly downloaded with outlook.office365.co

Post by tanstaafl »

It means the UID of the message changed. That causes the original to be ignored and copy of the message with a new UID to be fetched. This is typically due to a server bug though it can also occur if the server loses some of the information it needs to track what UIDs are assigned to what messages, or the messages are migrated to a different server.

There are many threads claiming this problem occurs with Exchange servers due to their not closely following the IMAP standards. Most of those threads are written by Outlook users.

AFAIK its not a Thunderbird bug if this doesn't occur for all accounts. If it occurred for all accounts then I'd suspect the search index for global search was corrupted, causing it to keep re-fetching messages.

https://answers.microsoft.com/en-us/mso ... 9fc88ce70c

https://answers.microsoft.com/en-us/mso ... 71de2ce302

https://serverfault.com/questions/42280 ... imap-mails
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