Times ago when I downloaded workshop maps and played them I can hear Cave Johnson speaking at the beginning.After I learned to add custom sounds to my maps ,having created some folders and put some sound files in the sound/ ,Cave Johnson didn't speak any more.But on my laptop he speaks.How to solve this problem?

try typing cm_reset_vo_progress in the console.

TheTobbell wrote:
try typing cm_reset_vo_progress in the console.

it works ! much thanks .