Index: ext/RMagick/rmmain.cpp
--- ext/RMagick/rmmain.cpp.orig
+++ ext/RMagick/rmmain.cpp
@@ -201,9 +201,7 @@ static inline void managed_memory_enable(VALUE enable)
 
 static void set_managed_memory(void)
 {
-    char *disable = getenv("RMAGICK_DISABLE_MANAGED_MEMORY");
-
-    if (disable)
+    if (1)
     {
         managed_memory_enable(Qfalse);
         return;
