Well, actually I mean empty the files out of it, leaving the empty folder intact. Mine is on my C: drive in
C:\Users\Jeff\AppData\Local\Lockheed Martin\Prepar3D v2\Shaders
And I have a macro that opens that folder and marks all files, which I then delete (permanently, not recycle bin). It helps sometimes to create fresh ones.
You no longer have a shader cache? How does that work?
You disabled it somehow? How do you know it was not working? Isn't it an automatic thing, and is required?