Note: This only works for VPK addons.Let's say you have a lot of mods, or mods you hold near and dear to your heart because they're so important and valuable to you.
But, you just want to play default Half-Life 2.
We can do that without moving or deleting anything. In fact, we can do everything from the Steam client.
To those who know how to set launch options, add this.
If you don't know how to set your Half-Life 2 launch options, here's how.
1. Right click Half-Life 2 in your steam library. A menu will show up. Click 'Properties', which is the option at the very bottom.
2. At that point, you should see a button that says 'Set launch options...'. Click that.
3. Copy and paste
-override_vpkinto the text field. Then, click 'OK'.
You're set to go. Half-Life 2 will play as if no mods were installed. If you want your mods back, follow the steps and remove the line from your launch options.