MacBook Air audio missing after Serato DJ Lite driver installation and improper uninstallation

Update

i have done a backup with Time Machine then I have initialised the disk by CMD + R-> then Disc Utility—>

Initialise disc (the only one I have is the 125 GB SSD MacOS HD)

Then reinstall MacOS Mojave from zero.

Everything was fine

i created a new account , log in and audio sound is perfectly ok.

so at least I m sure there is no any deep firmware damage.

then i re-installed the backup with Time Machine and my original account:

audio disappear no more available in any preferences.

And is not available in any account (also the new one I created).

Finally

I tried to unload kextaudio by this command

sudo kextunload /System/Library/Extensions/ AppleHDA.kext

ok, command executed.

then

sudo rm -rf System/Library/Extensions/ AppleHDA.kext

and after this command I get error: impossible to remove … not allowed.

do you know why?

i will continue thinking tomorrow how try to recover.

Hello thanks for answering me. Yes I run Disk Utility in the top left view i see APPLE SSD 128 Gb , then inside a "content" and inside Macintosh HD. Nothing else. I am not running any VPN no antiviruI run "SOS" on the Macintosh HD and seems all ok. Today i Went to AppleStore Genius bar where they suggested me to make a Timemachine backup (i did ) and then try to re-install MacOS Mojave by pressing COMMAND+R during reboot. I did. The process has taken 45 minutes and was succesfull. But at the restart (despite when i restart before to log in I hear a sound) when i log in with my admin user finally all sounds are lost as described before. I will try to provide you maybe more info with etrecheck. Any other idea meantime are welcome. thank you a lot.

Thanks for fast reply: I've installed Mac-app-cleaner but i don't find anymore any files linked to Serato Dj-Lite. So seems app was uninstalled correctly.

Problem remain that if I go to --> System Preferences --> Sound --> i get(after 5 mins of rolling coloured wheel !) the message "Preference Error! Impossible to load Sound preference" . And if I go Information on Mac --> system report ..> Hardware --> Sound: totally empty!

Thank you BDAqua for your kind help.

find below the EtreCheck report i generated

I hope usefulll

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Thank you but Disk Utility first aid was ok, no any errors detected.

Finally after 3 days I've founded a solution.

I recovered a very old back up (but at least with 80% of applications i needed). From my "corrupted" OS I've copied all my data : documents, download, desktop, images, movies, configurations of the browsers (all the data : config, password whatever) in an external disk.

Than i taken note of the applications i have installed since this old back up.

Then i have started the process to re-initialized disk (CMD+R) + reinstalled this backup with TimeMachine and then i was able to restart with my account working .

But this was a very old "status":

So Then i copied manually the files , updated the app, downloaded the new app, and now everything returned fine.

It was impossible to restore audio and performance in the original corrupted account (which was a "root" account so even worst). System also become incredibly slow (for instance if you tried to open a terminal windows it was taking some time, clicking some applications taken time: the problem was deep ).

I was 3 times at the Genius bar of AppleStore and at the end this was the only "safest" solution they suggested me .

I want really to thank you for your kind help and i hope this post can help other people in future.

Thank you

Long live Apple!

ciao!