Filters only run automatically on the Inbox, but a filter can be run manually on any folder. But there are a couple of add-ons compatible with TB 115:

https://addons.thunderbird.net/en-us/thunderbird/addon/extract-em/

https://addons.thunderbird.net/en-us/thunderbird/addon/mail-extractor/versions/1.6.1

Thank you for the reply, however neither add-on does what I want. Plus, I could not even get mail-extractor/versions/1.6.1 to run at all.

Any other ideas?

Filters only run automatically on the Inbox

Really? What is the option to send After Sending for then? There is no filter action to remove attachments from the message, but if the action existed looks like it should be possible to do what the OP wants…

sfhowes said

Filters only run automatically on the Inbox

Really? What is the option to send After Sending for then? There is no filter action to remove attachments from the message, but if the action existed looks like it should be possible to do what the OP wants…

Do some tests, and I think you'll find that After Sending automatically applies the filter to the Inbox after sending, not the Sent folder where you want the attachments deleted.

Apply filter when: √ Manually Run √ After Sending

Match all messages

Perform these actions: Add Star

Send a test message from the account where the filter is defined to one of my other addresses. Message saved to the account Sent folder is starred…