Cannot open shader file

I got this error today : Cannot open shader file -rez/shader/legacyshader.fxo
The well known ' send error report " also pops up

I googled it to look for answer and ended up on some hacking sites, now, don't get me wrong I don't hack, and I never did. I would prove it if someone knew how.

It prevents me from playing, so I'dd like a solution.

Screenshots will follow soon.

edit: screens

o55a3l.png
2w4zqtj.png

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