I've added the info in the top, to make it visible for as much people as possible. I also wrote here about it, because more people will be notified. It's nice gesture on R* part since a lot of music have been deleted.
I also recommend finding out some workaround for music restoration tool: https://www.pcgamingwiki.com/wiki/Grand_Theft_Auto_IV#Restore_removed_music if it doesn't work on R* version, since some people reported that launcher is capable of restoring modified files on launch after installation of language packs/fan translations, so probably it may affect this tool too. Disabling updates doesn't help. Maybe only offline play.