diff --git a/cmake/OpenMWMacros.cmake b/cmake/OpenMWMacros.cmake
index c3ba197e4..5f66705e7 100644
--- a/cmake/OpenMWMacros.cmake
+++ b/cmake/OpenMWMacros.cmake
@@ -169,7 +169,7 @@ macro (get_generator_is_multi_config VALUE)
 	if (CMAKE_VERSION VERSION_GREATER 3.9 OR CMAKE_VERSION VERSION_EQUAL 3.9)
 		get_cmake_property(${VALUE} GENERATOR_IS_MULTI_CONFIG)
 	else (CMAKE_VERSION VERSION_GREATER 3.9 OR CMAKE_VERSION VERSION_EQUAL 3.9)
-		list(LENGTH ${CMAKE_CONFIGURATION_TYPES} ${VALUE})
+		list(LENGTH "${CMAKE_CONFIGURATION_TYPES}" ${VALUE})
 	endif (CMAKE_VERSION VERSION_GREATER 3.9 OR CMAKE_VERSION VERSION_EQUAL 3.9)
 endmacro (get_generator_is_multi_config)