Rosetta and macOS 27: why games stop launching after the update

Updated 1 October 2026 · Uncork version 0.17.0 · Apple's wording checked against its pages on 1 October 2026

Short version: if Windows games on your Mac stopped launching after the update to macOS 27, install Rosetta 2 again. The update does not bring it back, and the compatibility layer these games run on today, almost everywhere, sits on top of Rosetta. The Terminal command is in the section below. Apple writes that Rosetta as a general-purpose tool for Intel apps ends with macOS 27, and macOS 28 keeps only a part of it for older games. That is the big question for the future of every app of this kind, Uncork included.

What happened

macOS 27 “Golden Gate” came out on 14 September 2026 and runs only on Macs with Apple Silicon. According to Apple's release notes for 27.0, if Rosetta was installed before, it does not come back by itself after the update: you have to install it again. Today almost all apps that run Windows games on a Mac execute Windows programs through Rosetta, so without it they do not start; the exception is the test ARM64 builds, described below. Heroic Games Launcher's tracker describes the error spawn Unknown system error -86 when Rosetta is missing (issue #5774, July 2026, macOS 27 beta), and the Porting Kit authors wrote on 20 September that after the update new installs in it fail until Rosetta is restored (their note).

How to fix it

Open Terminal and run:

/usr/sbin/softwareupdate --install-rosetta --agree-to-license

This is Apple's standard command. If you use Uncork, without Rosetta the app shows a banner with an “Install Rosetta” button that runs the same command; if the button does not work, use Terminal. We have not yet tried this button live on macOS 27. Your games and bottles stay where they are.

What happens in macOS 28

Apple writes that Rosetta as a general-purpose tool for Intel apps is available through macOS 27, and starting with macOS 28 it remains only for certain older, unmaintained games that rely on Intel-based frameworks (Apple's support page of 21 September 2026, Rosetta documentation). The macOS 27 release notes say the same more briefly: Intel-based software will no longer be compatible with macOS 28.0, excluding legacy games.

This wording is not new: it has been there since June 2025 (since WWDC25, per MacRumors' summary), and Apple has never published criteria for what counts as an “older game”. Whether Steam and a compatibility layer qualify is unknown; in our assessment, they do not look like “older games”. Beta versions of macOS have a mode for testing such games: according to Apple, Rosetta is turned off in it and non-game processes may crash. We have not tested Uncork in this mode yet.

Apple's own pages disagree. The developer news post of 1 September and the support page name macOS 27 as the last version with Rosetta, while the news post of 9 September names macOS 26 (1 September, 9 September). Apple has not published a correction: on 1 October 2026 the text of the 9 September post is unchanged. We go by the support page and the 27.0 release notes: in them Rosetta is present in macOS 27.

By the developers' own description, a path without Rosetta is so far only a test: an ARM64 build of the compatibility layer runs Windows programs another way. A preview of such a build came out on 31 July 2026; it has no D3DMetal, the Apple graphics library that Windows games on a Mac rely on today, and Direct3D 12 support is promised. The developers plan a release for early 2027.

Managed Macs: school and work

In macOS 27, administrators who manage Macs through MDM got a policy called App Settings. If it carries a list of allowed or denied programs, even an empty one, the system blocks programs that are unsigned, ad hoc signed or signed with an Apple Development certificate (Der Flounder's write-up of 24 September 2026). Before version 1.0.12 Uncork was signed with exactly an Apple Development certificate, so on a school or work Mac with such a policy it would, by that description, have been blocked. Since 1.0.12 it is signed with Developer ID, which, by the same description, is not caught by the block. The write-up covers managed Macs only and says nothing about personal ones, and we have not tested this on a managed Mac.

An administrator can hide the notice about Rosetta's future removal with the MDM key allowRosettaUsageAwareness (it appeared in macOS 26.4, and the notice is shown by default), but the key controls only whether the notice appears, not whether Rosetta works (Apple's schema).

What this means for Uncork

Uncork runs on top of Rosetta today, like almost all apps of this class, so this is the project's main risk for the coming year. We do not promise everything will work on macOS 28: it depends on what stays in the system and on whether D3DMetal appears for ARM64. For now, on macOS 27 the app shows a banner with an install button when Rosetta is missing.

What to do now

Stay on macOS 27 and do not update to macOS 28 until we have written here that we checked Uncork on it.
If games stopped launching after an update, install Rosetta again: the command is in the section above.
Apple does not give a release date for macOS 28: its support page calls it “the next major macOS release”.