Matrix Games Forums

On the options screen there is a box that if checked allows the building of colonies and mining facilities in other races systems. If this is not checked, does that also prevent other aliens from building stuff in your systems? If so, it does not appear to be working. Are there exceptions to this?

That option is only to prevent autobuilding those structures in other empires' systems (because you usually take a reputation hit for doing so). There's nothing that outright denies anybody the ability to do so.