The link you provided fixed my problem. Thank you for leading me to this solution.
The solution below from bdndc’s post fixed the issue for me. I disabled “Play sound when an alert is shown” in Comodo, and rebooted Windows 10.
Problem started occurring again. I enabled the “Play sound when an alert is shown” feature in Comodo. I ran an update to my sound card driver which first uninstalled my sound driver and required a reboot.
After reboot, alerts started working properly at this time and a sound played with Comodo alerts in Win10 notification tray (even with driver uninstalled, win10 must have loaded a driver.)
Next, installed updated sound card driver (update reported to fix issue with Win10 anniversary update) (old driver and alert issue worked fine for quite a while with anniversary update installed). rebooted.
Comodo is now working properly again with “Play sound when an alert is shown” enabled.
It either needed that setting checked with a reboot or the sound driver had something to do with it, but I don’t know because I did it all at the same time. A reboot may be be critical on this issue with enabling or disabling that “Play sound when an alert is shown” feature.