diff --git a/.mspec.constants b/.mspec.constants
index 6e09a4436..4da363371 100644
--- a/.mspec.constants
+++ b/.mspec.constants
@@ -146,6 +146,7 @@ Prime
 Private
 ProcFromMethod
 Psych
+RactorLocalSingleton
 REXML
 RUBY_SIGNALS
 RbReadline
diff --git a/default.mspec b/default.mspec
index 2ebd455fd..1e8f8893a 100644
--- a/default.mspec
+++ b/default.mspec
@@ -47,6 +47,5 @@ class MSpecScript
     /\wSpecs?$/,
     /^CS_CONST/,
     /^CSL_CONST/,
-    /^RactorLocalSingleton/,
   ]
 end