Add-on Notes
This summarizes the changes for Left 4 Dead 2's Add-ons from Left 4 Dead's.
AppID
The addoninfo.txt
file in your L4D2 add-on must have the proper app ID:
addonSteamAppID 550
If this isn't included, or if it's set to the Left 4 Dead 1 ID (500), VPK files will not be installed properly when users double click on them. (Or technically, theaddoninstaller.exe
program.)
VPK Install
If users double click a VPK while the game is not running, it gets copied to a temporary location under:
Steam\steamapps\SourceMods\addons
Then, when are launched, they look for add-ons in those directories, then moves them over to their own respective add-ons folder.