D3dref9.dll Guide

Errors involving d3dref9.dll—such as "file missing" or "not found"—usually occur because an application is attempting to use the instead of your physical graphics card. Common reasons include:

: Because it renders in software, it follows the Direct3D specifications exactly, serving as the "gold standard" for how a frame should look. d3dref9.dll

: It is primarily included in the DirectX 9.0c Developer Runtime . Developers use it to verify that their graphics code is logically correct, independent of hardware bugs. Errors involving d3dref9