# Does TLA+ Toolbox work on macOS 28?

> **Short answer: no, not on its own.** According to Homebrew’s package data (checked October 5, 2026), TLA+ Toolbox is Intel-only and its current download has no Apple silicon build. Apple says Intel-only apps stop running on Apple silicon Macs after macOS 27, apart from some older games. Keep86 is built to keep apps like this running, but we haven’t tested TLA+ Toolbox yet.

## Key facts

- Architecture: Intel-only (according to Homebrew’s package data, checked October 5, 2026)
- Homebrew package: tla+-toolbox (https://formulae.brew.sh/cask/tla%2B-toolbox), 677 installs in the last 365 days
- Website: https://lamport.azurewebsites.net/tla/toolbox.html
- Native Apple silicon version: None listed
- Keep86 status: Not tested yet
- Latest known version: 1.7.4
- Last verified: 2026-10-05

## Questions about TLA+ Toolbox

### Does TLA+ Toolbox work on Apple silicon?

Only through Rosetta 2. TLA+ Toolbox is Intel-only: an Apple silicon Mac runs it by translating its Intel code with Rosetta 2, which Apple supports in full until macOS 27.

### Does TLA+ Toolbox need Rosetta 2?

Yes, on every Apple silicon Mac. Apple has said that from macOS 28 Rosetta remains only for some older games, so Intel-only apps like TLA+ Toolbox stop opening.

### How can I keep using TLA+ Toolbox after macOS 28?

Stay on macOS 27 on this Mac, switch to an alternative, or run TLA+ Toolbox in a macOS 27 virtual machine (UTM, VirtualBuddy, Parallels). Keep86 runs that virtual Mac hidden and shows the app’s windows on your desktop; see the test status above.

## Sources

- Homebrew cask “tla+-toolbox” 1.7.4 requires Rosetta (Intel-only build) — https://formulae.brew.sh/cask/tla+-toolbox (2026-10-05)

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Architecture data partly from Homebrew (formulae.brew.sh), used under the BSD 2-Clause licence.
Source: https://keep86.com/apps/tla-toolbox