From what I can ascertain from my early-adopter experience, the compressed legacy content is the older, accumulated content from way back. If you are not interested in these and have no desire to reinstall then ignore them. Now, I'm not certain about the legacy content being reinstalled from the Poser.exe. I really need someone to investigate this. The Poser installer calls on executable files (.exe) for each of the categories original offered in the past. I notice that the final release Poser version website has no executables, just compressed files, I am assuming that no legacy content is installed on the initial installation of Poser. Again, someone would need to verify this for us.