I have discovered two problems with downloading headers in Thunderbird 3 (and SeaMonkey 2, which is pretty much the same).
To see both problems, in Thunderbird do the following:
- Subscribe to Msdn.en-US.msdnsandbox, and make sure you have the latest messages.
- Right-click the group name in the left pane and select "Mark newsgroup read".
- In the message list, mark just one message as not read (to keep it simple, pick one without any responses). You should see the group name go bold in the left pane , with (1) following to indicate 1 unread message.
- Right click the group name and select Properties.
- On the General Information tab, select "Rebuild index". At the current time there are 4068 messages in Msdn.en-US.msdnsandbox -- select to download them all.
- Watch the progress on the status bar. For me things move along pretty quickly, but when the count gets to either 2251 or 2401 it always stalls, and the message list remains blank.
- You can recover by closing the Properties window, selecting another group in the left pane, and then coming back to Msdn.en-US.msdnsandbox. Thunderbird will tell you there are more headers to download. Select to download them all, and this time it will finish.
- Note that all the messages are marked as read. This is not supposed to happen. With a normal NNTP server, Thunderbird remembers which messages were read/unread in the old index file and transfers this information to the new one.
I have reproduced this problem several times, using both SeaMonkey 2 on Windows 7, and Thunderbird 3 in an XP virtual machine.
One might think that the stalling was just a timeout issue because the bridge is slow. But things move along very well until the stall, and the stall always happens at the same place(s) -- 2251 or 2401 messages.
As to the read/unread messages, one would think this was a Thunderbird issue, but it does not happen with other NNTP servers. It seems to me there must be something different about the way that the bridge is delivering the headers.