diff --git a/sp/src/materialsystem/stdshaders/windowimposter_dx90.cpp b/sp/src/materialsystem/stdshaders/windowimposter_dx90.cpp
index 99ac7914..d24ac04b 100644
--- a/sp/src/materialsystem/stdshaders/windowimposter_dx90.cpp
+++ b/sp/src/materialsystem/stdshaders/windowimposter_dx90.cpp
@@ -7,9 +7,9 @@
 #include "BaseVSShader.h"
 #include "cpp_shader_constant_register_map.h"
 
-#include "sdk_windowimposter_vs20.inc"
-#include "sdk_windowimposter_ps20.inc"
-#include "sdk_windowimposter_ps20b.inc"
+#include "SDK_windowimposter_vs20.inc"
+#include "SDK_windowimposter_ps20.inc"
+#include "SDK_windowimposter_ps20b.inc"