Thunderbird hides older messages by changing status to 0009
I first noticed the problem about 1 month ago, a few days after I updated Thunderbird and compacted local folders. I was looking for an old message in one of my Local Folders's subfolders and discovered that messages received prior to a certain date of 2018 were gone. I opened then the same folder from a backup made prior to the update. The missing messages were not visible there either. However, when I checked the size of the folder's mbox file I found that that the backup file was much bigger. I opened it in Notepad and found all my missing messages there. I checked, in a text editor, the headers of the missing messages and found that none of them had the Mozilla status 0001, which is normal for received and read message. Their status was mainly 0009, that of a deleted message, and many other variations. I certainly did not delete these messages myself and they were not visible in Trash folder either, as deleted messages with status 0009 should, as I understand it. To make the missing messages visible again I edited the folder's mbox file, and manually changed their status to 0001. I checked all my other Thunderbird folders (I have about 30 for received files) and found the same problem in 1 more of them. After fixing the issue I thought it would not happen again. But today I came across the same problem. Messages received before Aug 2018 in another subfolder were missing. (It is possible that I just overlooked that folder when I was checking all of my folders for the problem 1 month ago). I checked the mbox file and they thankfully were still there but their status again is 0009. What might be going on? I've searched the internet on this problem and some suggest that it might be an Antivirus that corrupts mbox files. But in my case, Thunderbird process is listed on the exclusion list in Windows Defender.
Wšykne wótegrona (2)
It sounds like you have an auto delete set up either on that specific folder or on the account or on 'Local Folders' mail account.
Check account settings:
- Right click on mail account in folder pane and select 'Settings'
the 'Account Settings' window opens In left pane: For a pop mail account :
- Select 'Disc Space'
- Select 'Don't delete any messages'
Now check 'Local Folders' mail account
- Select 'Disc Space'
- Select 'Don't delete any messages'
- click on OK
Now check individual folder in Folder Pane.
- Right click on folder and select 'Properties'
- Select 'Retention Policy' tab
- Select 'Use my account settings'
OR
- uncheck 'Use my account settings'
- Select 'Don't delete any messages'
- click on OK
Thanks. The Retention Policy on all mail folders was 'Use my account setting' and I only had 3 POP accounts, all with 'Don't delete any messages'. So it did not look like that Thunderbird was supposed to delete old messages or limit their number in mail folders. Nevertheless I've changed each individual folder' retention policy to 'Don't delete any messages' just in case the POP account settings do not work as they are supposed to. I hope the problem will not return.