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You need to determine which base game the mod is for – Half-Life 2, Episode One or Episode Two. The issue is that thanks to SteamPipe, the locations of these files have changed. Gameinfo.txt tells Steam all the content that needs to be loaded. Navigate to the mod folder and open the gameinfo.txt file. If you’re not in luck, this is where things can get tricky.
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Now load up Steam and try it out, as some mods such as those using an SDK Base and new releases may be unaffected. The first step is to download and install the mod as usual, placing the folder in the Steam\SteamApps\sourcemods directory.
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