On one macOS Sonoma machine, Firefox launches very slowly and then crashes. On another Mac with the same macOS version, Firefox works normally. Even in Safe Mode, Firefox cannot start its GPU and socket subprocesses. Steps to Reproduce 1. Download the latest Firefox from the official Mozilla website. 2. Install it normally in /Applications. 3. Launch Firefox by double-click or from terminal. Firefox starts very slowly and then crashes or becomes unstable. When launching Firefox in Safe Mode: /Applications/Firefox.app/Contents/MacOS/firefox --safe-mode [Parent 1846, IPC I/O Parent] WARNING: Failed to launch gpu subprocess @MachCheckInListener TimedOut (Error:0) [Parent 1846, IPC I/O Parent] WARNING: Failed to launch socket subprocess @MachCheckInListener TimedOut (Error:0) [GFX1-]: Fallback remains SW-WR [GFX1-]: Failed to launch GPU process after 3 attempts • Reinstalling Firefox does not fix the issue. • Safe Mode does not fix the issue. • The problem appears to be related to Firefox child process initialization (GPU and socket processes). • The browser often starts in crash recovery state. • Automation tests fail with: “Browsing context has been discarded” Firefox is currently unusable on this machine due to repeated crashes and inability to initialize required subprocesses. • Any recommended workaround or diagnostic steps.