diff --git a/java/src/com/android/inputmethod/latin/LatinIME.java b/java/src/com/android/inputmethod/latin/LatinIME.java
index 2e5e4c3..54c6543 100644
--- a/java/src/com/android/inputmethod/latin/LatinIME.java
+++ b/java/src/com/android/inputmethod/latin/LatinIME.java
@@ -72,7 +72,8 @@
 import com.android.inputmethod.latin.inputlogic.InputLogic;
 import com.android.inputmethod.latin.inputlogic.SpaceState;
 import com.android.inputmethod.latin.personalization.DictionaryDecayBroadcastReciever;
-import com.android.inputmethod.latin.personalization.PersonalizationDictionarySessionRegister;
+import com.android.inputmethod.latin.personalization.PersonalizationDictionarySessionRegistrar;
+import com.android.inputmethod.latin.personalization.PersonalizationHelper;
 import com.android.inputmethod.latin.settings.Settings;
 import com.android.inputmethod.latin.settings.SettingsActivity;
 import com.android.inputmethod.latin.settings.SettingsValues;
@@ -463,7 +464,6 @@
         KeyboardSwitcher.init(this);
         AudioAndHapticFeedbackManager.init(this);
         AccessibilityUtils.init(this);
-        PersonalizationDictionarySessionRegister.init(this);
 
         super.onCreate();
 
@@ -515,10 +515,17 @@
         // the layout; at this time, we need to skip resetting the contacts dictionary. It will
         // be done later inside {@see #initSuggest()} when the reopenDictionaries message is
         // processed.
+        final SettingsValues currentSettingsValues = mSettings.getCurrent();
         if (!mHandler.hasPendingReopenDictionaries() && mInputLogic.mSuggest != null) {
             // May need to reset dictionaries depending on the user settings.
             mInputLogic.mSuggest.setAdditionalDictionaries(mInputLogic.mSuggest /* oldSuggest */,
-                    mSettings.getCurrent());
+                   currentSettingsValues);
+        }
+        if (currentSettingsValues.mUsePersonalizedDicts) {
+            PersonalizationDictionarySessionRegistrar.init(this);
+        } else {
+            PersonalizationHelper.removeAllPersonalizedDictionaries(this);
+            PersonalizationDictionarySessionRegistrar.resetAll(this);
         }
     }
 
@@ -590,7 +597,7 @@
             ResearchLogger.getInstance().onDestroy();
         }
         unregisterReceiver(mDictionaryPackInstallReceiver);
-        PersonalizationDictionarySessionRegister.onDestroy(this);
+        PersonalizationDictionarySessionRegistrar.onDestroy(this);
         LatinImeLogger.commit();
         LatinImeLogger.onDestroy();
         super.onDestroy();
@@ -610,7 +617,7 @@
                 mOptionsDialog.dismiss();
             }
         }
-        PersonalizationDictionarySessionRegister.onConfigurationChanged(this, conf);
+        PersonalizationDictionarySessionRegistrar.onConfigurationChanged(this, conf);
         super.onConfigurationChanged(conf);
     }
 
diff --git a/java/src/com/android/inputmethod/latin/personalization/PersonalizationDictionary.java b/java/src/com/android/inputmethod/latin/personalization/PersonalizationDictionary.java
index 596562f..9b2b981 100644
--- a/java/src/com/android/inputmethod/latin/personalization/PersonalizationDictionary.java
+++ b/java/src/com/android/inputmethod/latin/personalization/PersonalizationDictionary.java
@@ -27,7 +27,7 @@
 import android.content.Context;
 
 public class PersonalizationDictionary extends DecayingExpandableBinaryDictionaryBase {
-    private static final String NAME = PersonalizationDictionary.class.getSimpleName();
+    /* package */ static final String NAME = PersonalizationDictionary.class.getSimpleName();
 
     private final ArrayList<PersonalizationDictionaryUpdateSession> mSessions =
             CollectionUtils.newArrayList();
diff --git a/java/src/com/android/inputmethod/latin/personalization/PersonalizationDictionarySessionRegister.java b/java/src/com/android/inputmethod/latin/personalization/PersonalizationDictionarySessionRegistrar.java
similarity index 90%
rename from java/src/com/android/inputmethod/latin/personalization/PersonalizationDictionarySessionRegister.java
rename to java/src/com/android/inputmethod/latin/personalization/PersonalizationDictionarySessionRegistrar.java
index 542bda6..7696511 100644
--- a/java/src/com/android/inputmethod/latin/personalization/PersonalizationDictionarySessionRegister.java
+++ b/java/src/com/android/inputmethod/latin/personalization/PersonalizationDictionarySessionRegistrar.java
@@ -19,7 +19,7 @@
 import android.content.Context;
 import android.content.res.Configuration;
 
-public class PersonalizationDictionarySessionRegister {
+public class PersonalizationDictionarySessionRegistrar {
     public static void init(final Context context) {
     }
 
@@ -32,6 +32,9 @@
     public static void onRemoveData(final Context context, final String type) {
     }
 
+    public static void resetAll(final Context context) {
+    }
+
     public static void onDestroy(final Context context) {
     }
 }
diff --git a/java/src/com/android/inputmethod/latin/personalization/PersonalizationHelper.java b/java/src/com/android/inputmethod/latin/personalization/PersonalizationHelper.java
index d55cae1..38b22e5 100644
--- a/java/src/com/android/inputmethod/latin/personalization/PersonalizationHelper.java
+++ b/java/src/com/android/inputmethod/latin/personalization/PersonalizationHelper.java
@@ -17,10 +17,13 @@
 package com.android.inputmethod.latin.personalization;
 
 import com.android.inputmethod.latin.utils.CollectionUtils;
+import com.android.inputmethod.latin.utils.FileUtils;
 
 import android.content.Context;
 import android.util.Log;
 
+import java.io.File;
+import java.io.FilenameFilter;
 import java.lang.ref.SoftReference;
 import java.util.Locale;
 import java.util.concurrent.ConcurrentHashMap;
@@ -96,4 +99,47 @@
             return dict;
         }
     }
+
+    public static void removeAllPersonalizedDictionaries(final Context context) {
+        removeAllDictionaries(context, sLangUserHistoryDictCache,
+                UserHistoryDictionary.NAME);
+        removeAllDictionaries(context, sLangPersonalizationDictCache,
+                PersonalizationDictionary.NAME);
+    }
+
+    private static <T extends DecayingExpandableBinaryDictionaryBase> void removeAllDictionaries(
+            final Context context, final ConcurrentHashMap<String, SoftReference<T>> dictionaryMap,
+            final String dictNamePrefix) {
+        synchronized (dictionaryMap) {
+            for (final ConcurrentHashMap.Entry<String, SoftReference<T>> entry
+                    : dictionaryMap.entrySet()) {
+                if (entry.getValue() != null) {
+                    final DecayingExpandableBinaryDictionaryBase dict = entry.getValue().get();
+                    if (dict != null) {
+                        dict.clearAndFlushDictionary();
+                    }
+                }
+            }
+            dictionaryMap.clear();
+            if (!FileUtils.deleteFilteredFiles(
+                    context.getFilesDir(), new DictFilter(dictNamePrefix))) {
+                Log.e(TAG, "Cannot remove all existing dictionary files. filesDir: "
+                        + context.getFilesDir().getAbsolutePath() + ", dictNamePrefix: "
+                        + dictNamePrefix);
+            }
+        }
+    }
+
+    private static class DictFilter implements FilenameFilter {
+        private final String mName;
+
+        DictFilter(final String name) {
+            mName = name;
+        }
+
+        @Override
+        public boolean accept(final File dir, final String name) {
+            return name.startsWith(mName);
+        }
+    }
 }
diff --git a/java/src/com/android/inputmethod/latin/personalization/UserHistoryDictionary.java b/java/src/com/android/inputmethod/latin/personalization/UserHistoryDictionary.java
index 868f21c..c23bc9b 100644
--- a/java/src/com/android/inputmethod/latin/personalization/UserHistoryDictionary.java
+++ b/java/src/com/android/inputmethod/latin/personalization/UserHistoryDictionary.java
@@ -29,8 +29,7 @@
  * cancellation or manual picks. This allows the keyboard to adapt to the typist over time.
  */
 public class UserHistoryDictionary extends DecayingExpandableBinaryDictionaryBase {
-    /* package for tests */ static final String NAME =
-            UserHistoryDictionary.class.getSimpleName();
+    /* package */ static final String NAME = UserHistoryDictionary.class.getSimpleName();
     /* package */ UserHistoryDictionary(final Context context, final Locale locale) {
         super(context, locale, Dictionary.TYPE_USER_HISTORY, getDictNameWithLocale(NAME, locale));
     }
diff --git a/java/src/com/android/inputmethod/latin/settings/Settings.java b/java/src/com/android/inputmethod/latin/settings/Settings.java
index 9bd2b93..64f53b5 100644
--- a/java/src/com/android/inputmethod/latin/settings/Settings.java
+++ b/java/src/com/android/inputmethod/latin/settings/Settings.java
@@ -371,8 +371,12 @@
     }
 
     public void writeLastUsedPersonalizationToken(byte[] token) {
-        final String tokenStr = StringUtils.byteArrayToHexString(token);
-        mPrefs.edit().putString(PREF_LAST_USED_PERSONALIZATION_TOKEN, tokenStr).apply();
+        if (token == null) {
+            mPrefs.edit().remove(PREF_LAST_USED_PERSONALIZATION_TOKEN).apply();
+        } else {
+            final String tokenStr = StringUtils.byteArrayToHexString(token);
+            mPrefs.edit().putString(PREF_LAST_USED_PERSONALIZATION_TOKEN, tokenStr).apply();
+        }
     }
 
     public byte[] readLastUsedPersonalizationToken() {
diff --git a/java/src/com/android/inputmethod/latin/utils/FileUtils.java b/java/src/com/android/inputmethod/latin/utils/FileUtils.java
index 83c1e7c..22b0fbb 100644
--- a/java/src/com/android/inputmethod/latin/utils/FileUtils.java
+++ b/java/src/com/android/inputmethod/latin/utils/FileUtils.java
@@ -17,6 +17,7 @@
 package com.android.inputmethod.latin.utils;
 
 import java.io.File;
+import java.io.FilenameFilter;
 
 /**
  * A simple class to help with removing directories recursively.
@@ -30,4 +31,18 @@
         }
         return path.delete();
     }
+
+    public static boolean deleteFilteredFiles(final File dir, final FilenameFilter fileNameFilter) {
+        if (!dir.isDirectory()) {
+            return false;
+        }
+        final File[] files = dir.listFiles(fileNameFilter);
+        boolean hasDeletedAllFiles = true;
+        for (final File file : files) {
+            if (!deleteRecursively(file)) {
+                hasDeletedAllFiles = false;
+            }
+        }
+        return hasDeletedAllFiles;
+    }
 }