"Yep, some users have reported a problem
that the aliens don't always show up.
We'll be taking a look at this, because you definitely want two aliens in any alien game.
Producer\Designer, Sid Meier's Alien Crossfire
(posted by Tim Train at 10.26.1999 21:42 in
alt.games.firaxis.alpha-centauri + comp.sys.ibm.pc.games.strategic)
The problem is still valid. If you play an IP game and let the slots being unoccupied by human players free as "random", it may happen that you get one Alien faction only.
The same may happen, if a human player selects an Alien faction, but the 2nd Alien faction isn't set. Then the games sometimes doesn't set in a free random spot the 2nd Alien.
In both cases you have to start the game new and correct it, as the game is badly calculating if one Alien faction exists only.
If you like to play without Alien, then you have to set all free spots, if you like to play with Alien, you have to set both Alien (maybe one played by human and the other by AI), even if you let free the other unoccupied slots as "random".