Question on Happiness

Try creating an emotionless race it stops all issues with low happiness it does have the side effect of you not getting bonuses for high happiness but it stops the system wide riots.

Other things which help

1 defend each planet as well as possible before people get unhappy troops fighters mine fields and weapon platforms as a minimum
2 build urban pacification facilities in advance of riots as they work better as a preventative
3 keep your enemies out of star systems and beat them if they do get in
4 don’t expand too fast
5 get as many cultural achievements as these seem to make your citizens happier and sociology stops people getting unhappy from being at war
6 play a naturally happy race

Another thing to be careful of is your choice of happiness type. A "bloodthirsty" race is harder to keep happy, and a (really poorly named) "neutral" race is /really/ hard to please. There's a reason all the stock AIs are "peaceful", regardless of how aggressive or xenophobic they are.

"Good morning, Pooh Bear," said Eeyore gloomily. "If it /is/ a good morning," he said. "Which I doubt," said he.

-How do you choose an happiness type?

-In happiness.txt :
Our Troops on Planet := -2
Is it anger decrease PER troop? Or do you have to have a certain number of them?

EDIT: Found the answer: It's -2% anger per turn for every 10 troops.

"Good morning, Pooh Bear," said Eeyore gloomily. "If it /is/ a good morning," he said. "Which I doubt," said he.

There is nothing like that when you create the race (apart form minister Agressive/Moderate/Defensive but that's not it). I think this existed in a previous version of the game, then got scrapped for some reason... so now every empire created is peaceful? Or is it linked to your governement and society choices?

"Good morning, Pooh Bear," said Eeyore gloomily. "If it /is/ a good morning," he said. "Which I doubt," said he.

Woops, my bad... I thought we were talking about Space Empires 5.