Hi guys I have found a method to verify the files of gta 5 directly from the rockstar launcher.
1 First, go where you have installed the gtav.exe my is in D:\Programmi\GTAVLauncher.exe
2 Now create a shortcut of gtavlauncher.exe, right click and hit proprieties, now you have to add -verify after your directory here an example.
apply and save
3 Done, hit the shortcut and the verify will start!
Hope this helps !
Non Steam version? You can still easily verify files.
Create a new text document named “commandline.txt” and place it in the root game folder with “-verify” (without the quotes) in it.