I have made a little mailbox to reproduce KBNS.00.0.082. Don't worry about Jean-Marc_Clément: he's the character played by Yves Montand in the film ``Let's Make Love'' or something, with Marilyn Monroe as well. But I am now beginning to doubt whether this name really does need an accent... Oh well! :-)
I did get a feeling that the problem had something to do with the é in the name, because when I transformed é to e in a similar mailbox that had the problem, everything was fine again.
It may also have something to do with how fast you are issuing the commands to Mail.app and/or in what sequence, but I'm not sure of that.
Anyway, this crashes Mail.app for me (five times in five):
- do make in a shell while in this directory
- start up Mail.app and click Mailboxes (the button in Active.mbox)
- arrange the window and the Mailboxes panel so you have some room around them
- place small windows near the Mailboxes button you just clicked, and
- near the entry for KBNS.00.0.082 in the Mailboxes panel
- quit Mail
- launch Mail
- the instant that Active.mbox appears, click on Mailboxes
- the instant Mailboxes appears, double-click KBNS.00.082
- Mail crashes
Well, actually I'm not sure anymore it's the speed that counts, just the sequence of actions.
My configuration: 8-MB NeXTstation ``Classic''. This may be important: if your system is too fast, you may have to switch off some memory using a known procedure, to get some paging activity, or else you may want to copy a large mbox in front of what's in this mbox.