Many of the maps I play are from the workshop, on sandbox mode. But the shiny textures go all weird and reflect the missing textures image on most objects. I do have TF2, Half-Life 2 and the episodes, Portal 1 & 2 (if that matters at all) and CSS all mounted. And played each of those games at least once. Some maps that give me issues are the SSBM Fourside map and the Pokemon Goldenrod City map. It’s a real pain to wait a while for the map to load, only to have to type mat_specular 0 after that for some more loading. I am using an autoexec to do this for me now but I still want to know why this is happening. Verified all my games too.
I know what are you talking about I have the same issue when I download a map from workshop.