diff -r 95732422055c openide.util/src/org/openide/util/Utilities.java
--- a/openide.util/src/org/openide/util/Utilities.java	Wed Jul 02 10:16:53 2008 +0200
+++ b/openide.util/src/org/openide/util/Utilities.java	Wed Jul 02 13:42:08 2008 +0200
@@ -2378,6 +2378,9 @@
      * # rename of whole package
      * org.someoldpackage=org.my.new.package.structure
      *
+     * # class was removed without replacement
+     * org.mypackage.OldClass=
+     *
      * </PRE>
      * Btw. one can use spaces instead of <code>=</code> sign.
      * For a real world example
diff -r 95732422055c settings/src/org/netbeans/modules/settings/convertors/SerialDataConvertor.java
--- a/settings/src/org/netbeans/modules/settings/convertors/SerialDataConvertor.java	Wed Jul 02 10:16:53 2008 +0200
+++ b/settings/src/org/netbeans/modules/settings/convertors/SerialDataConvertor.java	Wed Jul 02 13:42:08 2008 +0200
@@ -114,8 +114,11 @@
         
         SerialDataConvertor.SettingsInstance si = createInstance(null);
         if (isModuleEnabled(si)) {
-            instance = si;
-            lkpContent.add(instance);
+            // 137240 - if instanceName is empty string, it doesn't provide instance
+            if (si.instanceName().length() > 0) {
+                instance = si;
+                lkpContent.add(instance);
+            }
         }
         lkpContent.add(this);
         node = new SerialDataConvertor.NodeConvertor();
diff -r 95732422055c settings/test/unit/src/META-INF/netbeans/translate.names
--- a/settings/test/unit/src/META-INF/netbeans/translate.names	Wed Jul 02 10:16:53 2008 +0200
+++ b/settings/test/unit/src/META-INF/netbeans/translate.names	Wed Jul 02 13:42:08 2008 +0200
@@ -40,3 +40,4 @@
 # Old repackaging.
 org.UnknownClass=org.netbeans.modules.settings.convertors.FooSetting
 org.netbeans.modules.settings.convertors.ObsoleteClass=org.netbeans.modules.settings.convertors.FooSetting
+org.netbeans.modules.settings.convertors.UnknownClass=
diff -r 95732422055c settings/test/unit/src/org/netbeans/modules/settings/convertors/SerialDataConvertorTest.java
--- a/settings/test/unit/src/org/netbeans/modules/settings/convertors/SerialDataConvertorTest.java	Wed Jul 02 10:16:53 2008 +0200
+++ b/settings/test/unit/src/org/netbeans/modules/settings/convertors/SerialDataConvertorTest.java	Wed Jul 02 13:42:08 2008 +0200
@@ -581,6 +581,16 @@
         assertNull("There shouldn't be provided InstanceCookie for disabled module", ic);        
     }
 
+    /** If class name is mapped to an empty string in META-INF.netbeans/translate.names,
+     * InstanceCookie should not be created. */
+    public void testUknownClass137240() throws DataObjectNotFoundException {
+        final FileObject valid = lfs.findResource("/Settings/org-netbeans-modules-settings-convertors-FooSettingUnknownClass.settings");
+        assertNotNull(valid);
+        DataObject ido = DataObject.find(valid);
+        InstanceCookie ic = (InstanceCookie) ido.getCookie(InstanceCookie.class);
+        assertNull("InstanceCookie issued for unknown class.", ic);
+    }
+
     public void testDeleteOfUnrecognizedSettingsFile () throws Exception {
         final FileObject corrupted = lfs.findResource("/Settings/org-netbeans-modules-settings-convertors-FooSettingUnrecognizedSettingsFile.settings");
         assertNotNull(corrupted);
diff -r 95732422055c settings/test/unit/src/org/netbeans/modules/settings/convertors/data/mf-layer.xml
--- a/settings/test/unit/src/org/netbeans/modules/settings/convertors/data/mf-layer.xml	Wed Jul 02 10:16:53 2008 +0200
+++ b/settings/test/unit/src/org/netbeans/modules/settings/convertors/data/mf-layer.xml	Wed Jul 02 13:42:08 2008 +0200
@@ -90,6 +90,16 @@
 </settings>
 ]]>
         </file>
+
+        <file name="org-netbeans-modules-settings-convertors-FooSettingUnknownClass.settings">
+<![CDATA[<!DOCTYPE settings PUBLIC "-//NetBeans//DTD Session settings 1.0//EN" "http://www.netbeans.org/dtds/sessionsettings-1_0.dtd">
+<settings version="1.0">
+    <module name="org.netbeans.modules.settings.xtest"/>
+    <instanceof class="org.netbeans.modules.settings.convertors.UnknownClass"/>
+    <instance class="org.netbeans.modules.settings.convertors.UnknownClass"/>
+</settings>
+]]>
+        </file>
         
         <!-- SerialDataConvertorTest.testCorruptedSettingsFile -->