I get the same behavior and error. Worked fine yesterday.
I should say, I am running ubuntu 20.04.
I was able to revive Steam by running steam --reset.
Not ideal since it resets all shader caches and Proton settings but at least Steam works again (for now).
Steam goes right back to crashing after it finished downloading all shader caches.
Hello @DomiStyle, the symptoms you've described and the utlmemory.h assertion in your log reads like the issue being tracked at #7813. Feel free to add your experience to the older issue report.
Closing as a duplicate.
Nothing extracted yet.
Your system information
Please describe your issue in as much detail as possible:
Steam crashes on startup.
Log: https://gist.github.com/DomiStyle/f0bc81c962f895dfd76c66971481ce33
Steps for reproducing this issue: