steam

steam.exe is the Steam client, Valve's PC gaming launcher and storefront. Steam is the largest PC gaming platform in the world by a wide margin, hosting most of the v1 anchor titles in this Field Guide (Counter-Strike 2, Apex Legends, Rainbow Six Siege, Fortnite, PUBG, The Finals, and Escape from Tarkov since its 2025 Steam release, among many others). The launcher dates to 2003 and has continuously expanded into chat, friends, broadcasting, and a CEF-based store renderer.

What installing it does to your system: Steam runs as a user-mode process with no kernel driver of its own. It does auto-start on Windows boot by default (configurable in Steam's settings), and it stays resident in the background to handle friend presence, chat, downloads, and pending updates. Companion processes you will see alongside it: steamservice.exe (the elevation-helper service, also curated) and steamwebhelper.exe (the Chromium/CEF UI renderer that draws the store and library, also curated). Steam stores payment information, a friend graph, your purchased library, and game-specific cloud saves.

If you have Steam installed, this process is expected. The Steam Guard mobile authenticator is the practical hygiene step for the account itself; keep auto-updates on for the client.