I had this problem as well. During one evening, I always got the hang at "Shutting down ALSA..." when rebooting or shutting down the PC.
Perhaps not coincidentally, I was having network problems the same evening, due to maintenance from my ISP. (Basically, my local network was fine, I just didn't have an Internet connection). The next evening, Internet was fine, and the hang was gone. Also, after the first hang, all sound channels were muted (as in Bug #288039). aplay -l: **** List of PLAYBACK Hardware Devices **** card 0: Intel [HDA Intel], device 0: CONEXANT Analog [CONEXANT Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: Intel [HDA Intel], device 1: Conexant Digital [Conexant Digital] Subdevices: 1/1 Subdevice #0: subdevice #0 -- MASTER storing ALSA mixer element values during shutdown hangs nondeterministically due to internal alsa-plugins pulse check https://bugs.launchpad.net/bugs/274995 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs