Tony_O said

This is a follow-up question. The answer I got did not help. It referred me to https://support.mozilla.org/en-US/kb/archived-messages . That tells me to select the messages, not more than 2000 at a time. I can select only 1 message at time. Also, I have to select a destination folder, using Edit > Account Settings. The "edit" point is "bleak" and does not respond. Thanks, Tony_O .

I think you need to learn about multiselecting.

http://xenos-email-notes.simplesite.com/417754237

I don't understand why you think you need to go to account settings to select a folder. Please explain what advice you're trying to follow.