diff --git a/src/PrusaSlicer.cpp b/src/PrusaSlicer.cpp
index a3247b929..2becb8071 100644
--- a/src/PrusaSlicer.cpp
+++ b/src/PrusaSlicer.cpp
@@ -7,10 +7,13 @@
     #include <Windows.h>
     #include <wchar.h>
     #ifdef SLIC3R_GUI
+    extern "C" 
+    { 
         // Let the NVIDIA and AMD know we want to use their graphics card
         // on a dual graphics card system.
         __declspec(dllexport) DWORD NvOptimusEnablement = 0x00000001;
         __declspec(dllexport) int AmdPowerXpressRequestHighPerformance = 1;
+    }
     #endif /* SLIC3R_GUI */
 #endif /* WIN32 */
 
diff --git a/src/PrusaSlicer_app_msvc.cpp b/src/PrusaSlicer_app_msvc.cpp
index 5b01751b9..ee8cdf696 100644
--- a/src/PrusaSlicer_app_msvc.cpp
+++ b/src/PrusaSlicer_app_msvc.cpp
@@ -8,10 +8,14 @@
 #include <wchar.h>
 
 #ifdef SLIC3R_GUI
+//Turn on high power graphics for NVidia cards on laptops (with built in graphics cards + Nvidia cards)
+extern "C" 
+{ 
 	// Let the NVIDIA and AMD know we want to use their graphics card
 	// on a dual graphics card system.
 	__declspec(dllexport) DWORD NvOptimusEnablement = 0x00000001;
 	__declspec(dllexport) int AmdPowerXpressRequestHighPerformance = 1;
+}
 #endif /* SLIC3R_GUI */
 
 #include <stdlib.h>