Dear Sir or Madame, I posted this issue already earlier (https://support.mozilla.org/en-US/questions/1428881?utm_campaign=questions-reply&utm_source=notification&utm_medium=email#answer-1613810), but it still persists. Zited from my earlier report: The usual process that happened when deleting or separating attachments from e-mails was that a copy of the email without the attachment was produced by Thunderbird and the original email was deleted. This is not longer working. When I delete an attachment, the original email containing the attachment is not deleted. So I have two versions of the email in my postbox, one with the attachment, the other without. Probably I'm missing a setting? Thunderbird version 115.3.3 (32-Bit) Still happening with 115.12.2 (32-Bit) Sincerely yours, Markus Piotrowski