Missing textures and UI menu

So for some a lot of textures are pitch black and im missing the UI (i think its a new bug and will be patch soon), but problem with textures started a long time ago, my friend got that problem too. We dont know what’s causing it, please help.

Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valve’s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.