Map Download troble

Hi i like to go on community servers to go on hg, surf , san, ect. Some maps i try to play on for the first time i click join and download the map, then after 100% some maps say "missing map..". dont judge me but i play on a mac but my friend can download all them maps and he has a mac. So i figured its not my operating system. So is there a way to fix this? If so, comment on this.

Thanks sincerely,

Scrandy

Map Download troble