Valve has announced that Steam will no longer support macOS 11 Big Sur starting October 15, 2025. If you’re still running Big Sur, you’ll need to upgrade to macOS Monterey or later to keep using the platform. Otherwise, the Steam client and any purchased games will stop working after the cutoff.
The move comes down to compatibility. Steam depends on an embedded version of Google Chrome, which no longer functions on older macOS versions. Future updates to Steam will also require security features only available in macOS 12 and above. Without them, the client can’t operate reliably or safely.
Security Risks for Outdated macOS
Apple stopped providing security updates for Big Sur in 2023. That leaves systems running the OS vulnerable to malware and performance issues. According to Valve, continuing to use Steam on unsupported systems increases the risk of account theft and software crashes. The company is urging users to upgrade “sooner rather than later” to avoid service disruptions and potential security threats.
Valve’s warning isn’t just about its own client. Devices running unpatched operating systems are exposed to new malware variants that exploit outdated system components. Once infected, these systems can leak Steam credentials or damage the gaming experience by crashing the app or slowing down performance.
Valve detailed the change in an official support post, linking it to both the Chrome dependency and Apple’s discontinued support for Big Sur. You can find their full statement here.
Native Support for Apple Silicon Moves Ahead
The Big Sur cutoff is part of a broader shift. Valve recently rolled out a beta version of its native Apple silicon client. This followed Apple’s move to phase out Rosetta 2, the translation layer that allowed Intel-based apps to run on M-series Macs. Early testers of the native Steam build have reported significantly faster launch times and a smoother user interface.
With Apple focusing entirely on its custom silicon chips and sunsetting older compatibility layers, Valve’s decision aligns with the platform’s future direction. It also signals Steam’s continued commitment to supporting Mac gaming, just not on legacy software.
The beta client was released shortly after Apple’s WWDC 2025 keynote, where the company reiterated its long-term plans for hardware and software integration.
What You Need to Do
If you’re still using Big Sur, update your Mac to at least macOS Monterey before October 15, 2025. Otherwise, you won’t be able to launch Steam or any games tied to your account. Apple provides upgrade instructions and compatibility checks on its official support page.
