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Outlook emails are no longer moving to POP folder under Thunderbird 2 days ago

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I have 4 POP accounts with outlook and 1 IMAP account that I access using Thunderbird. In the last two days ( since release 102.10) it appears that on all the POP acounts Thunderbird is not sending a Delete to the outlook server. This means that every time I do "Get Messages ", I receive the same set of messages as last time. When I login into the outlook server via Firefox I can see all the messages sitting in the Inbox marked as not having been read, when they used to be moved automatically into the POP folder under Deleted. I have not changed any configuration settings, in ether Thunderbird or Outlook. The Outlook setting is "Don't allow devices and apps to delete messages from Outlook. It will move the messages to special POP folder instead" and Thunderbird 's option "Leave messages on server" is unchecked. These settings haven't been changed in years, the only difference is that Thunderbird has been updated. This problem has been reported by several people to Microsoft (see https://answers.microsoft.com/en-us/outlook_com/forum/all/outlook-emails-are-no-longer-moving-to-pop-folder/f330a21b-6779-42ef-9937-1cb1a2dd023a) but It seems that the problem may be in Thunderbird not sending a Delete after downloading.

I have 4 POP accounts with outlook and 1 IMAP account that I access using Thunderbird. In the last two days ( since release 102.10) it appears that on all the POP acounts Thunderbird is not sending a Delete to the outlook server. This means that every time I do "Get Messages ", I receive the same set of messages as last time. When I login into the outlook server via Firefox I can see all the messages sitting in the Inbox marked as not having been read, when they used to be moved automatically into the POP folder under Deleted. I have not changed any configuration settings, in ether Thunderbird or Outlook. The Outlook setting is "Don't allow devices and apps to delete messages from Outlook. It will move the messages to special POP folder instead" and Thunderbird 's option "Leave messages on server" is unchecked. These settings haven't been changed in years, the only difference is that Thunderbird has been updated. This problem has been reported by several people to Microsoft (see https://answers.microsoft.com/en-us/outlook_com/forum/all/outlook-emails-are-no-longer-moving-to-pop-folder/f330a21b-6779-42ef-9937-1cb1a2dd023a) but It seems that the problem may be in Thunderbird not sending a Delete after downloading.

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This might be an issue with Outlook - whilst some people are using Thunderbird, another person was accessing via gmail and also see same issue.

You say "Thunderbird 's option "Leave messages on server" is unchecked." So, that should send a delete signal.

You say " POP account - This means that every time I do "Get Messages ", I receive the same set of messages as last time. "

However, whether delete signal was sent or not would not mean you should get another download of same emails. This makes me wonder if you have an issue with the 'popstate.dat' file.


When emails are downloaded to a POP account, thunderbird keeps a record of what was previously downloaded in a 'popstate.dat' file, so when it checks the server Inbox on the next occasion, it does not download something previously downloaded.

In your case it seems to be failing which implies something is wrong with the 'popstate.dat' file.

  • Menu icon > Help > More Troubleshooting Information
  • Under 'Application Basics' - half way - Profile Folders - click on 'Open Folder'

A new window opens showing the contents of your profile name folder.

  • Exit Thunderbird now.
  • Click on 'Mail' folder
  • Click on the pop mail account name folder

You should see one 'popstate.dat' file.

Do you see several files with similar name maybe with an additional number ? eg: popstate-1.dat

If that 'popstate.dat' file has got corrupted maybe it keeps recreating a new one, so it has no idea what was previously downloaded. The more common culprit for causing this problem is if you have something scanning profile eg: Anti-Virus and/or CCLeaner or WiseCleaner type programs which is deleting the popstate.dat file.

Advise: do not allow any scanning of Profile name folder by any product as it can cause havoc with files with session data etc. Make the thunderbird profile folder exempt from scanning.

Advise you delete any 'popstate.dat' or 'popstate-1.dat' files.

This means a new one will get created when you start Thunderbird and as it contains no data, it will cause a fresh download of anything in the server 'Inbox'.

Advise you logon to webmail account and remove all previously downloaded emails into another folder to prevent another download or do nothing and allow the full download.

Start Thunderbird.