me and my partner in science havent been able to play co-op the past 2 days. when we try to connect, It displays (for me atleast) the loading screen, with the first picture of atlas and p-body jumping, but the dots on the bottom dont light up. then it goes to the title screen and says connectino to game server failed. has the co-op doing anything fishy to you recently? I need help.

It can be caused by changed game files(Hammer has this nasty habit of saving modified instances when you didn't ask for it). Both you and your partner, try verifying game cache in Steam.

Networking problems maby, but are you two running custom maps or are you running the default?

dinnesch wrote:
It can be caused by changed game files(Hammer has this nasty habit of saving modified instances when you didn't ask for it). Both you and your partner, try verifying game cache in Steam.

I wouldn't think this was a problem given that if they were playing anything it would be a compiled map.

Are you playing stock coop? Or a custom map?

Well if they are connecting to each other they will be going to the lobby and not a custom map, so this would not be a problem.
Try verifying the cache of Portal2 (both you and your partner) good chances is that one of the files is corrupt.

It's okay guys. i did what the first poster said and it worked. close topic