Halflife 2: A.I disabled

[chiptracy]

I'm playing HL2,the screen appear a sentence:
NODE GRAPH OUT OF DATE.REBUILDING
A.I.DISABLED
Game still play but the bots in game stop work
What is it?
Why does it become that?
please show me repair? Thanks!!!

 

[Calhoun]

Is it a legal copy of the game?

 

[ComradeBadger]

Buy the game.