diff --git a/Bizware/BizHawk.Bizware.BizwareGL.OpenTK/IGL_TK.cs b/Bizware/BizHawk.Bizware.BizwareGL.OpenTK/IGL_TK.cs
index 364bb05f51..7bf1154656 100644
--- a/Bizware/BizHawk.Bizware.BizwareGL.OpenTK/IGL_TK.cs
+++ b/Bizware/BizHawk.Bizware.BizwareGL.OpenTK/IGL_TK.cs
@@ -354,7 +354,8 @@ namespace BizHawk.Bizware.BizwareGL.Drivers.OpenTK
 
 		public void Internal_FreeShader(Shader shader)
 		{
-			GL.DeleteShader((int)shader.Opaque);
+			var sw = shader.Opaque as ShaderWrapper;
+			GL.DeleteShader(sw.sid);
 		}
 
 		public void BindPipeline(Pipeline pipeline)