diff --git a/src/citra_qt/debugger/graphics_framebuffer.cpp b/src/citra_qt/debugger/graphics_framebuffer.cpp
index c30e75933..5902c9ad2 100644
--- a/src/citra_qt/debugger/graphics_framebuffer.cpp
+++ b/src/citra_qt/debugger/graphics_framebuffer.cpp
@@ -346,5 +346,8 @@ u32 GraphicsFramebufferWidget::BytesPerPixel(GraphicsFramebufferWidget::Format f
         case Format::RGBA4:
         case Format::D16:
             return 2;
+        case Format::Unknown:
+            ASSERT_MSG(false, "Unknown frame buffer format.");
+            return 0;
     }
 }