diff --git a/reactos/subsystems/win32/win32k/objects/coord.c b/reactos/subsystems/win32/win32k/objects/coord.c
index 67b57b366eb..275a76ead52 100644
--- a/reactos/subsystems/win32/win32k/objects/coord.c
+++ b/reactos/subsystems/win32/win32k/objects/coord.c
@@ -587,7 +587,7 @@ NtGdiScaleViewportExtEx(
     {
         _SEH2_TRY
         {
-            ProbeForWrite(pSize, sizeof(LPSIZE), 1);
+            ProbeForWrite(pSize, sizeof(SIZE), 1);
 
             pSize->cx = pdcattr->szlViewportExt.cx;
             pSize->cy = pdcattr->szlViewportExt.cy;
@@ -633,7 +633,7 @@ NtGdiScaleWindowExtEx(
 
         _SEH2_TRY
         {
-            ProbeForWrite(pSize, sizeof(LPSIZE), 1);
+            ProbeForWrite(pSize, sizeof(SIZE), 1);
 
             X = pdcattr->szlWindowExt.cx;
             if (pdcattr->dwLayout & LAYOUT_RTL) X = -X;