Sorry about that fragment. I ended up backing up everything except email, reinstalling the OS and then setting up email again. (But you will lose any applications you installed on the N800.) But before I did that I went into Yahoo mail and moved all but my recent email into an "old" folder. Then I downloaded email again into the N800.

This is obviously a workaround, but I could not find a way in either the Nokia email client or the Claws Mail program to tell it to ignore old email on the server.

Ken