If you use all 3, you'll be fine. I did science and it worked, it's just the warning system L4D2 has that was tiggered by something in there.

Because every part of Yama VPK has the same "yama.txt" (mission file) to tell the game they're work together. It's common and can be seen at other campaigns with huge size.

What about update GameMaps version?

yup this make i can't play with friends. only can play in single player

The problem I had yesterday: I had yama and yama_v6 from game maps, at map 3 I had the "version does not match the server version" error with the old yama and the v6 from gamemaps even tho this Workshop item redirects to it. And the workshop item conflicts with itself part 2 3 4 are conflicting with each others, such a shame, i was able to connect after subing to this AND restarting the game however it would still need to be fixed, that and the gamemaps version so that people can join.

It's one of the best campaigns for L4D2 so I guess someone is going to do it hopefully :)

it's normal but lazy and dirty as ♥♥♥♥ from the developers end

when i try this mod, suddenly the game got crashed twice