12TB Valve archive leak includes early Portal 2 builds and hints of Half-Life 2: Episode Three

A massive 12 terabyte archive containing old Valve development files, spanning from 2003 to 2013, has appeared online, sparking excitement among fans. Gabe Follower, a Twitter/X user, initially discovered the leak on Friday, which reportedly includes early versions of Portal 2, Left 4 Dead, and CS:GO, along with assets from the cancelled Portal prequel F-Stop.

The leak also potentially contains material related to Half-Life 2: Episode Three, as evidenced by a Weaponizer model, previously linked to the game but now used as a placeholder in Portal 2. Additionally, a fully playable Left 4 Dead beta build from June 2008 was found, complete with an early HUD, a work-in-progress lobby screen, and unused audio, including lines initially recorded for character Zoey by Alésia Glidewell before being replaced by Jen Taylor in the final game.

The archive is believed to originate from Valve's old Steam2 content-delivery infrastructure, which was phased out for SteamPipe in the early 2010s. Unlike a recent cyber attack that exposed Valve's European shipping partner's customer data, this leak does not involve any of Valve's own game data. Valve has not commented on the latest leak.

This discovery comes after a trustworthy report in 2024 revealed datamined assets supporting a leak involving an actor involved in Half-Life 2: Episode Three, suggesting that Valve may be working on a new Half-Life project, codenamed HLX. While Half-Life 3 was reportedly in development between 2013 and 2014, it was cancelled due to its dependence on the unfinished Source 2 engine.