diff --git a/test/TEST.ROOT b/test/TEST.ROOT
index e8e3fda5f850af7114ddf495e43c775eb21aa329..91c9dacebb2bce7f404fb11cb844644895a623ce 100644
--- a/test/TEST.ROOT
+++ b/test/TEST.ROOT
@@ -9,4 +9,4 @@ keys=2d dnd i18n
 othervm.dirs=java/awt java/beans java/rmi javax/accessibility javax/imageio javax/sound javax/print javax/management com/sun/awt sun/awt sun/java2d sun/pisces sun/rmi
 
 # Tests that cannot run concurrently
-exclusiveAccess.dirs=java/rmi/Naming sun/management/jmxremote sun/tools/jstatd
+exclusiveAccess.dirs=java/rmi/Naming java/util/prefs sun/management/jmxremote sun/tools/jstatd