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Thunderbird cannot reliably parse its own mbox files

david.ledger
david.ledger
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Many of my mailboxes on the IMAP server just emptied. They were still there in my Ubuntu '.thunderbird' ImapMail directory. I have created some replacement mailboxes in 'Local Folders' and copied mbox files from the ImapMail area to the Local Folder area, removing the .msf files just created by Thunderbird. I then used the Properties->Repair Folder on each of the the new Local and filled-in-the-background mailboxes. Many worked fine and I was able to repopulate the IMAP server mailboxes using drag in Thunderbird. Some, however, were mis-parsed, producing 'From-less' and Subject-less messages containing part messages. Thunderbird seems unable to reliably parse mbox files created by itself. I note that they are not strict mbox format, having a '-' instead of an envelope address on the delimiting '^From ' line. (I am a retired Unix SysAdmin, so used to the command line)

Many of my mailboxes on the IMAP server just emptied. They were still there in my Ubuntu '.thunderbird' ImapMail directory. I have created some replacement mailboxes in 'Local Folders' and copied mbox files from the ImapMail area to the Local Folder area, removing the .msf files just created by Thunderbird. I then used the Properties->Repair Folder on each of the the new Local and filled-in-the-background mailboxes. Many worked fine and I was able to repopulate the IMAP server mailboxes using drag in Thunderbird. Some, however, were mis-parsed, producing 'From-less' and Subject-less messages containing part messages. Thunderbird seems unable to reliably parse mbox files created by itself. I note that they are not strict mbox format, having a '-' instead of an envelope address on the delimiting '^From ' line. (I am a retired Unix SysAdmin, so used to the command line)

All Replies (2)

Wayne Mery
Wayne Mery
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Doesn't make sense...

What version? What mail provider? Even non-Inbox folders emptied?

Helpful?

david.ledger
david.ledger Question owner
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Thanks for your reply.

It's 115.18.0 (64-bit) running on Ubuntu 20.04.6 115.18.0 (64-bit)

The ISP is NamesCo in the UK

The Inbox is the least affected. I have 34 top level mailboxes with over 200 lower level nested mailboxes. Some were unaffected, but most were emptied.

About three weeks ago I changed my hosting from a name reflecting the fact that I used to host websites to a name that is my personal email address domain (previously hosted under the former). They transferred the IMAP tree across. At first I assumed that the ISP had seen a 'new' email account appear with over 4GB of messages and just deleted some. That now seems unlikely. They can restore my emails - at a cost of £30 per mailbox, which is ridiculously expensive. All had settled down after a couple of days.

I do run a few simple rules in Thunderbird, but nothing that can empty any mailboxes. I also use MailMate on a couple of older Macs, but only one of then filters, and they are to remove known junk from my Junk mailbox. Doesn't touch any other mailbox. Almost all of these MailMate filters only act on three other email accounts with a different ISP that haven't been affected in any way. I mainly use Thunderbird on Ubuntu for all my email handling.

It does seen odd that Thunderbird claims to used standard mbox maiboxes, but does not.

It also seems odd that when I open an ImapMail mailbox that has been copied into a freshly created Local Folder mailbox, Thunderbird can fail to parse it properly, even though it created the original itself.

Thanks, David

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