I have a large number of message filters which divert messages to folders on Subject. So messages I sent were diverted to those folders on sending. Mea Culpa Emails I send to a X@yahoo.co.uk are not saved in my default sent folder. I have checked the setting in Account Settings. If I send to Y@other CC X@yahoo.co.uk , the message does get saved. I am using POP to send/receive emails. This seems to have started in December 2023. I am using Thunderbird 115.8.0 running in Debian Buster. I would really appreciate a solution to this isssue. Thanks