December 2020
Open Steam, Right Click on Apex Legend In Game Select Menu then Verify Files. Some files will be missing. Verify files again
March 2021
What fixed it for me wasn't changing any sound setting. I simply went to the game files in steam and verified the integrity and there were two files that had to be reacquired. And it started right up.
November 2022
Got it all of a sudden. It worked no problem in friday, and came out like this on saturday. I have reinstalled Apex in Steam, verified integrity, toyed with sound preferences etc. Nothing unusual had been done and yet it refuses to work any longer.