Your system information

• Steam client version (build number or date): 1770954559 (Built: Feb 13 2026 03:35:38)

• Distribution (e.g. Ubuntu): CachyOS (Arch Linux rolling)

• Opted into Steam client beta?: [Yes]

• Have you checked for system updates?: [Yes]

• Steam Logs: steam-logs.tar.gz

• GPU: Nvidia RTX 4070 SUPER (Driver: 590.48.1)

Description:
I experienced a massive memory leak where the steam service consumed 17.6 GB of RAM, causing a system-wide Out-Of-Memory (OOM) crash that killed other applications (like Discord).

What I expected:
Steam to manage memory usage normally during background updates and game initialization.

What actually happened:
The Steam client beta entered a race condition. The logs show two specific events happening simultaneously right before the memory spike:

A background manifest download started (client-update.fastly.steamstatic.com).

mod.io services initialized for AppID 1066780 (Transport Fever 2).

Immediately after these two events overlapped, memory usage spiraled to 17.6GB until the system killed the process.

Relevant log snippet:

[13:55:36] Downloading manifest: https://client-update.fastly.steamstatic.com/...
[13:57:01] [Info][Core] Initializing mod.io services
[13:57:01] [Trace][ModManagement] Loading mod collection from storage
...
[13:59:52] [email protected]: Consumed ... 17.6G memory peak.

Steps for reproducing this issue:

1. Launch Steam Client Beta on CachyOS (Nvidia 590.xx drivers).
2. Ensure a Steam Client update is pending or downloading in the background.
3. Launch a game that utilizes mod.io services (e.g., Transport Fever 2).
4. Observe system memory usage via top or htop as the mod.io service initializes.