Half Life 2 and Half Life 2:Lost Coast Mounting Problem

[Rattle]

When I bought Garry's Mod, I bought it along with Counter Strike:Source and Team Fortress 2 was already installed on my computer. I have recently bought and succesfully installed Half Life 2 and Half Life 2:Lost Coast. But when I look at the list which has a list of games that Garry's Mod has succesfully mounted and can use, only Counter Strike:Source and Team Fortress 2 appear. Half Life 2 and Lost Coast also appear, but they have a box with a red X in them. I have tried uninstalling and reinstalling Garry's Mod but that will not fix the problem. Please help me with this issue, I really want to play Half Life 2 and Lost Coast maps in Garry's Mod.

[Xathule]

I have this problem as well it's really annoying as i love the game but half of the content is unlocked via half life souce

[moudyda]

It mounts just fine with MY Gmod, but the maps aren't showing.