Mail.app: The message “subject” could not be moved to the mailbox “(null)”

[Dr_Maybe]

When I press the backspace key to delete messages I get this message in a dialog box:

The message “Ipsum Subject line” could not be moved to the mailbox “(null)”
The destination mailbox “(null)” does not allow messages to be moved to it.
[OK]

I think it started happening after a force quit of Mail.app.

Is there a way to repair the settings or the database so that I can delete messages with backspace again?

If I move the messages to the trash "on my mac" it works, but if I move it to the "master" Trash can I get the same message.

 

[anna1966]

Same issue

Did you ever find a solution as I am experiencing exactly the same problem.