13-23:48:48.452 17_48 -EXC- System.ArgumentException: An item with the same key has already been added. Key: 554 How do I track this down?
Item (minigunDoubleDroneSmall) or Block (OxygenGenerator) 554 is already using that ID number and you've added a custom block/item which is also using that ID. Use an unoccupied ID number.
What I thought. I had added Oxygen Generator back into default scenario by removing the comments from it and its template. For some reason started getting this error and could not access a small constructor after being placed. Swapped out the blocks.ecf made changes again but did not touch generator this time and it all works fine.