Your system information

• Steam client version (build number or date):
• Distribution (e.g. Ubuntu): Manjaro
• Opted into Steam client beta?: No
• Have you checked for system updates?: Yes

Please describe your issue in as much detail as possible:

Due to a bug in alsa 1.1.4 64bit and 32bit applications can not use dmix at the same time (http://mailman.alsa-project.org/pipermail/alsa-devel/2017-May/121055.html). Recieving a game invitation with notification sounds turned on will lead to the error message
ALSA lib pcm_dmix.c:1077:(snd_pcm_dmix_open) unable to create IPC shm instance
followed by a segfault. Disabling the notification sound will resolve the problem.

While the music player will print the same alsa error message, it will not crash the client.

The bug in alsa has been fixed with version 1.1.4.1, still, being unable to play a sound should not crash the client

Steps for reproducing this issue:

1. Use a 64bit system and alsa 1.1.4 (no pulseaudio) with dmix
2. start a 64bit media player and play sound with it
3. start steam client and recieve a game invitation (notification sound needs to be turned on)