For some reason, when I go to the little game controller at the bottom right corner, All 3 half life 2 games have a folder with a red circle next to them. I can’t mount the games, though Left 4 Dead 2 and Team Fortress 2 have a box with a check mark next to them. I have bought all 3 games, installed them and have run them, but it still won’t work. They were mounted before this latest update but not in this one.
Follow this tutorial for all of your Half-Life games.