Compiz/Unity doesn't start at login

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http://askubuntu.com – Out of a sudden after I logging in to the 'Ubuntu' session Unity or maybe Compiz doesn't start anymore (actually I'm not sure wether it is Compiz or Unity). I can start Unity manually with setsid unity & and put the command as a startup script but that's not how it should be. I also tried a lot of "solutions" but none of them helped: checked for activated 'Unity' module in ccsm reinstalled lightdm reset Compiz and Unity reinstalled all Compiz/Unity packages many more... The question now is, how do I get Compiz/Unity to be started propperly at login again? I'm on 12.10 with Intel grap (HowTos)