Apple’s abandoned Copland operating system can now be explored in a browser through an experimental Power Mac emulator. The project offers a rare look at Apple’s intended modern replacement for System 7, but also highlights why the company eventually cancelled it: Copland remained unstable and incomplete, with key features existing mainly as plans.

The emulator runs D11E4, the final developer build, released in June 1996, and may require users to intervene when it encounters errors. Apple cancelled Copland later that year after prolonged delays, bought NeXT, and used NeXTSTEP as the foundation for Rhapsody and eventually Mac OS X, while incorporating some Copland features into Mac OS 8 and 9. The browser version was enabled by 11 AI-assisted patches to the DingusPPC emulator.