diff --git a/src/d3d9/d3d9_adapter.cpp b/src/d3d9/d3d9_adapter.cpp
index 5ae10210a..d166d7138 100644
--- a/src/d3d9/d3d9_adapter.cpp
+++ b/src/d3d9/d3d9_adapter.cpp
@@ -114,6 +114,9 @@ namespace dxvk {
           DWORD           Usage,
           D3DRESOURCETYPE RType,
           D3D9Format      CheckFormat) {
+    if(unlikely(AdapterFormat == D3D9Format::Unknown))
+      return D3DERR_INVALIDCALL;
+
     if (!IsSupportedAdapterFormat(AdapterFormat))
       return D3DERR_NOTAVAILABLE;