After the last Obsidian upgrade to 0.15.6 in my Ubuntu 22.04 TLS with KDE, I got a message «EMFILE: too many open files» when trying to run the application whatever vault I tried to open.
After searching a bit, I found this webpage where there is a workaround than can used to run Obsidian in the meantime the issue is fixed.
You just have to increase the max_user_instances in the system by runing this command as root:
echo 1024 > /proc/sys/fs/inotify/max_user_instances