Black boxes around explosions (Please help!)

So for a while now I’ve had black boxes around my explosions, I’ve searched everywhere for a solution but to no avail, I’ve reinstalled gmod, verified came cache, but nothing.
This is what it looks like:

It happened to me before, and fixed itself, now it’s back. Help please.

You’re basically missing content or missing a file for that particular particle. Have you launched ALL of your source engine based games and made sure THEY are all mounted?

Yep, got all of that.