then you need to verify integrity of game files, so steam can download the missing files

Unfortunately no

it has no sound for edar now ?
that's weird , are you sure you only deleted the edar .bnk in published folder instead of in the game folder ?

please check if there is WwiseDefaultBank_WW_ZED_Evil_DAR.bnk file in your game folder :
SteamLibrary\steamapps\common\killingfloor2\KFGame\BrewedPC\WwiseAudio\Windows

or try validate the game files to make sure it work properly

and after removing the sound there is no

you just need to delete the
WwiseDefaultBank_WW_ZED_Evil_DAR.bnk

in
My Games\KillingFloor2\KFGame\published\BrewedPC\WWiseaudio\Windows

What if I want to return the default d.a.r. sounds, but forgot to save them?

awesome