This is for the R* version.
( Need the steam version? ----> Click )


===ROCKSTAR Version===
Navigate to your gtav install folder. ( View file extensions, hidden/system protected files )
Compare your folder/files to the screenshot - delete anything NOT in the screenshot.
( Ignore date, time, type, size - leave commandline.txt IF you use it ) -----
And then ===> VERIFY.
(R* version - use gtavlauncher.exe -verify in command prompt
(or adjust your gtavlauncher shortcut -.-)
(There is also a playgtav -verify)

http://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=772966437
At the very least - dinput8.dll and/or dsound.dll need to be removed.

You may also want to check this link in the cases of update/verifying/downloading issues-
https://support.rockstargames.com/hc/en-us/articles/212226788



Original link --- R* mod removal / folder cleaning -
https://psteamcommunity.yuanyoumao.com/app/271590/discussions/0/350532795338017215/