All HL2-specific content is gone for some reason

All HL2 content (or all episodic content, I suppose) is gone from GM all of a sudden. When I try to start a new game (of any game mode), all HL2 and episodic maps are gone from the list entirely, and when I boot up one of my maps for my custom gamemode all of the episodic textures and items are missing (I get error signs and the pink-and-black checkerboards). I made sure that all of the HL games are checked in that content box on the main menu, validated and defragmented, and restarted both steam and my computer. Still missing.

This error came out of nowhere, and apparently I’m the only one getting it. WTH is going on?

SteamPipe is going on, I suggest you get used to it.

It’s funny how nearly nobody knew a thing about this!

Okay, I put both episodes onto steam pipeline, so now it all shows up in garry’s mod. However, I can’t load Episode 2 in the sdk now, and some episodic models (though not the episodic textures, for some reason) are missing in Garry’s mod. Apparently they’re rolling out new SDKs, but they don’t have anything for HL2, so some of my EP2 content is still bugged.

Anyone know how to fix this? Most of the stuff I’ve seen is for CS or HLDM. In fact, I think I remember seeing some stymied CS mappers saying they could map in EP2 without any issues.