ChatGPT Mac App Not Working? How to Fix It (2026)
Update — May 12, 2026: The certificate revocation went live on schedule on May 8, 2026. If your ChatGPT, Codex, Codex CLI, or Atlas Mac app now refuses to open and shows a “damaged” or “cannot be verified” warning, this guide still works; the fastest fix is a fresh download from chatgpt.com/download, since the in-app updater is no longer reachable from any build signed with the revoked certificate. On May 8, 2026, OpenAI revoked the macOS code-signing certificate it had used to sign ChatGPT, Codex, Codex CLI, and Atlas through April 2026. From that day on, macOS Gatekeeper refuses to launch any version still signed with the old certificate, so […]
