[eagleton]

Depopulation of planets by multiple transports has been fixed in one of the new beta Versions. You can find this int the beta-patch thread that was posted by Shrapnelgames. Population Transports are supposed to take population from planets with more than 1.000 million people and take it to planets with less than 500 million people. Unless it is out, you can stop the problem of depopulation by building only small transports. I never had problems with that.