Hello Wim, I am the current upstream maintainer and warming up the issue. Would you mind to join the discussion at the upstream ticket?
<https://github.com/bit-team/backintime/issues/1016>
I have questions about your "expected behavior":
* no backup is made when the external drive is not mounted
To my current understanding BIT is not able to know if the backup destination need to be mounted or not.
I have some ideas, but would like to discuss them upstream. Regards, Christian Buhtz
