I'm experiencing the same symptom. I've enabled system-wide PulseAudio in /etc/asound.conf
pcm.pulse { type pulse } ctl.pulse { type pulse } pcm.!default { type pulse } ctl.!default { type pulse } when gdm3 starts and plays a sound through PulseAudio when the login screen pops up, but unfortunately since PulseAudio service has not been started yet (PulseAudio is run as a per-session daemon which is Debian's default) , it fails and stuck there for serveral seconds. So I removed the configs in /etc/asound.conf and created $HOME/.asoundrc with the same content. then logout and login again, gdm3 will play the sound directly through Alsa instead of PulseAudio and does not stuck any more. I've also tested that by totally removing PulseAudio and using Alsa, the symptom will not show itself either.