Hey. I just go BM:S and noticed that my mainmenu is white.
Any fix? 
Can you… umm… give us more info about it? Maybe a screenshot?
I got the same issue, i’ll take a screenshot and repost it here! By the way, I’m under Wine on Ubuntu
Change yuor resolution, Menu goes fine!
Your computer’s not powerful enough to support it… upgrade.
How do you know this?
WHITE usually means either your system’s GPU is failing or it’s far too low end to handle the game and can’t render anything on the engine.
It happened to me with another client years ago. My computer couldn’t render some things in a RTS I played, and it was a white mesh (the model rendered fine - no textures) it worked fine after I upgraded. I’m not going to go into the technical details, it’ll go above your head quickly unless you know A LOT about computers. Suffice to say, the data output from Black Mesa’s engine overwhelms your computer’s CPU/GPU and it can’t render some of the elements because it can’t keep up with the data flow.
Edit: There’s other things you can try. Reduce the resolution and keep it in full screen. This will reduce the number of pixels the CPU/GPU need to render and free up some of the load.