Sending Mail Offline in Thunderbird

Thunderbird 2 is a really great IMAP client, but today while I was on a three-hour flight, I decided to work offline to clean out my inbox. Many of the emails I transferred to other folders required a reply, so I wrote replies and queued them up for sending once I returned to terra firma. That's when the trouble began.

Once on the ground, I put Thunderbird back in online mode. I was going to select the synchronize function so that all my queued messages could be sent and my moved messages placed in the correct folders. But before I could do this, Thunderbird sensed it was connected and started moving messages.

That Thunderbird automatically started moving the requested messages is not a problem. What is a problem is that Thunderbird did not automatically send the messages I had queued. It left them in the "Unsent" folder in my local folders and never told me about it. (It turns out I had several messages sitting there that I never knew about from years ago.)

I figured out that I could right-click on the "Unsent" local folder and ask it to send unsent messages, but then other problems surfaced. All the messages were apparently sent. (I say "apparently"; I can only trust Thunderbird until I hear back from the recipients.) Unlike in online mode, Thunrderbird did not flag the messages being replied to (which had already been moved to various folders) as having been replied to. But morse than that, Thunderbird did not place copies of the sent messages in my IMAP "Sent" folder.

Thunderbird's offline mode seems to work fine if you're just moving and deleting emails. But if you want to queue messages for sending, beware: offline sending doesn't have complete functionality. Unfortunately this is a deal-breaker for me, so the next time I'm in the air for three hours, I'll have to find something else to do unless I grab one of those new flights with an Internet connection.