If you copy&paste AB data files from one data base to another then it is not enough to just copy&paste them but in AmiBroker you have to create the symbols of those data files first. Only then they will be visible. So either make a text file symbol list that you import via ASCII import in AmiBroker or create the symbols one after another manually in AmiBroker. Then close AB and copy&paste the data file from the other database to the new one and start AB again.