diff --git a/CMake/DolphinLibraryTools.cmake b/CMake/DolphinLibraryTools.cmake
index f7f0bce46e..025900dad5 100644
--- a/CMake/DolphinLibraryTools.cmake
+++ b/CMake/DolphinLibraryTools.cmake
@@ -62,7 +62,7 @@ function(dolphin_find_optional_system_library library bundled_path)
     else()
       set(prefix ${upperlib})
     endif()
-    if((NOT ${found}) AND (NOT ${RESOLVED_USE_SYSTEM_${upperlib}} STREQUAL "AUTO"))
+    if((NOT ${prefix}_FOUND) AND (NOT ${RESOLVED_USE_SYSTEM_${upperlib}} STREQUAL "AUTO"))
       message(FATAL_ERROR "No system ${library} was found.  Please install it or set USE_SYSTEM_${upperlib} to AUTO or OFF.")
     endif()
   endif()