Missing a texture!

Today i started playing gmod and everything that should be slightly shiny (guns, Barney’s shoes, car bumpers, and many more.) had that translucent pink/black checker you get when you are missing a model, so annoying i havent been deleting things from my gmod folder, i dont have a clue what has caused it, anyone know how i can get the texture back?
i was thinking maybe it isn’t missing, but an addon has somehow replaced this texture with another which doesn’t exist, if that is possible.

It could be an addon.

is it only on certain maps?

it may be missing env_cubemap

its on everything, ragdolls, props, cars…

But does it also happen to these objects on any level you play on (such as gm_construct, gm_flatgrass, etc.)

Also could you post your PC specs?

it happens on every map, it isn’t because of my pc being too bad, i have had Gmod for years

i got rid of an addon which was not working, and it is fixed. took ages to find tho, i have loads of addons