I started download and play the l4d2 campaigns,there was so many error or pink/black surface.

After that, I install L4D2_Addon_Support.exe from
[link removed]

It help me fix so many error and pink/black.

Sorry for my bad English

You can get add on support from Steam it self. Why would you download it from a third-party area? Hmmm.

Yeah this usually happens to pirate versions

I thought that was why.

cloudlee99 - We appreciate that you are trying to help, but there is no reason to post a link to files that any legitimate user can already get through their Steam client. This site does not support pirated software and your link would only be useful for that purpose.

That is the files to fix some missing texture and model in download campaigns or map

Yes, except for that fact that 1. Steam already has Addon Support on it, making the link and this topic pointless, and 2. the only people who would need that link are people who got an illegal version of the game.

yes, we all know what you mean, but the addon support files are part of the Steam download - as Gunzers has said, only illegal copies of the game would have the pink textures and errors in the first place, and so would need those files to be downloaded separately.