Hi @flachtyp , thanks for reaching out about this. Sorry to hear you've had trouble demolishing your old harbour, and I'll be happy to help you look into this. Sorry for the delay in getting back to you, too.
Can you tell me what happens if you save and then reload the game? This lets the game load all the assets fresh, so we'll be able to see if it still loads the boxes.
Can you also check our troubleshooting guide for me? In particular, please make sure you are doing the verifying game files and running as admin steps from it. This makes sure the game has all the resources it needs to be doing what it needs to do.
Let me know if either of those steps helps. If not, I'll reach out to our dev team to get this looked into. Thanks!