Thanks for getting in touch. That’s certainly unexpected! I’m unable to reproduce this issue in my local instance (running 2020.2.16) and the --clean argument is recognized on my export. Can you let me know which version of Octopus you’re currently running? I’ll have a dig through the history of this command, as maybe it was added in a later version than what you’re running? It’ll at least allow me to attempt to reproduce this in the correct version.
Thanks for following up so quickly! I had a look at the release notes stretching back to before 3.10 and it looks like this --clean argument in the migrator’s export command was added in server version 3.11.13. You can reference the issue here.
If you’re unable to upgrade to latest, you can also find all previous versions available for download at the following link.
I hope that helps! Let me know how you go, or if you have any further questions going forward.