How to clear the game's cache
From Wolfire Games Wiki
Sometimes it can help to clear the game's cache. Here is how you can do that:
Mac
Delete the following folder:
Macintosh HD/Users/~/Library/Application Support/Lugaru 2/Data
Where '~' is your username.
Windows
Delete the following folder:
My Documents\Wolfire\Overgrowth\Data
NOT Program Files\Wolfire\Overgrowth\Data!)