"Blender --background hangs indefinitely -- user prefs corruption, not the script"

A previously working blender --background --python gen.py asset pipeline starts hanging indefinitely at full app init. Near-zero CPU, no output. blender --version returns instantly, confirming the binary is fine. Restarting or retrying changes nothing.

Blender user preferences or addon state is corrupted. The --background flag still loads the user config directory (prefs, addons, startup file). If a crash, a misbehaving addon, or stale session state corrupted the user prefs, the init path blocks forever. The audio-device probe is a second known init staller on some systems.

The diagnostic that separates this from a busted install: --version returns instantly (binary fine) while --background --python stalls (init path).

Add --factory-startup -noaudio to every headless invocation in your pipeline tooling:

blender --background --factory-startup -noaudio --python gen.py -- "$@"

• --factory-startup skips loading user preferences and addons entirely
• -noaudio removes the audio-device probe as a second init staller

Generator scripts should not depend on user prefs anyway. If your script genuinely needs user prefs, delete and regenerate the Blender user config directory instead.

--factory-startup forces Blender to use built-in defaults instead of reading the user config directory. Since the corruption lives in prefs/addon state (not the binary or the script), bypassing that path eliminates the hang. -noaudio removes a second blocking probe that can stall on machines where the audio device is unavailable or wedged. Together they make headless invocations deterministic and independent of host state.