diff --git a/server/shadow/shadow_surface.c b/server/shadow/shadow_surface.c
index 62c449e4a..156c4b1b3 100644
--- a/server/shadow/shadow_surface.c
+++ b/server/shadow/shadow_surface.c
@@ -40,9 +40,9 @@ rdpShadowSurface* shadow_surface_new(rdpShadowServer* server, UINT16 x, UINT16 y
 	surface->y = y;
 	surface->width = width;
 	surface->height = height;
-	surface->scanline = ALIGN_SCREEN_SIZE(surface->width, 4) * 4;
+	surface->scanline = ALIGN_SCREEN_SIZE(surface->width, 32) * 4;
 	surface->format = PIXEL_FORMAT_BGRX32;
-	surface->data = (BYTE*)calloc(ALIGN_SCREEN_SIZE(surface->height, 4), surface->scanline);
+	surface->data = (BYTE*)calloc(ALIGN_SCREEN_SIZE(surface->height, 32), surface->scanline);
 
 	if (!surface->data)
 	{