diff --git a/src/main/java/fr/unix_experience/owncloud_sms/engine/ASyncSMSRecovery.java b/src/main/java/fr/unix_experience/owncloud_sms/engine/ASyncSMSRecovery.java
index 889b3dd..4a7ffb6 100644
--- a/src/main/java/fr/unix_experience/owncloud_sms/engine/ASyncSMSRecovery.java
+++ b/src/main/java/fr/unix_experience/owncloud_sms/engine/ASyncSMSRecovery.java
@@ -68,7 +68,7 @@ public interface ASyncSMSRecovery {
 				while (obj.getLong("last_id") != start) {
 					JSONObject messages = obj.getJSONObject("messages");
 					Iterator<?> keys = messages.keys();
-					while(keys.hasNext()) {
+					while (keys.hasNext()) {
 						String key = (String)keys.next();
 						if (messages.get(key) instanceof JSONObject) {
 							JSONObject msg = messages.getJSONObject(key);
@@ -76,25 +76,43 @@ public interface ASyncSMSRecovery {
 							int mbid = msg.getInt("mailbox");
 							// Ignore invalid mailbox
 							if (mbid > MailboxID.ALL.getId()) {
+								Log.e(ASyncSMSRecovery.TAG, "Invalid mailbox found: " + msg.getString("mailbox"));
 								continue;
 							}
 
-							String address = msg.getString("address");
+							String address;
+							String body;
+							int type;
+							try {
+								address = msg.getString("address");
+								body = msg.getString("msg");
+								type = msg.getInt("type");
+							}
+							catch (JSONException e) {
+								Log.e(ASyncSMSRecovery.TAG, "Invalid SMS data found: " + e.getMessage());
+								continue;
+							}
+							MailboxID mailbox_id = MailboxID.fromInt(mbid);
+
+							// Ignore already existing messages
+							if (smsDataProvider.messageExists(address, body, key, mailbox_id)) {
+								publishProgress(nb);
+								continue;
+							}
 
 							ContentValues values = new ContentValues();
 							values.put(Telephony.Sms.ADDRESS, address);
-							values.put(Telephony.Sms.BODY, msg.getString("msg"));
+							values.put(Telephony.Sms.BODY, body);
 							values.put(Telephony.Sms.DATE, key);
-							values.put(Telephony.Sms.TYPE, msg.getInt("type"));
+							values.put(Telephony.Sms.TYPE, type);
 							values.put(Telephony.Sms.SEEN, 1);
 							values.put(Telephony.Sms.READ, 1);
 
-							MailboxID mailbox_id = MailboxID.fromInt(mbid);
 							// @TODO verify message exists before inserting it
 							_context.getContentResolver().insert(Uri.parse(mailbox_id.getURI()), values);
 
 							nb++;
-							if ((nb % 100) == 0) {
+							if ((nb % 5) == 0) {
 								publishProgress(nb);
 							}
 						}
diff --git a/src/main/java/fr/unix_experience/owncloud_sms/providers/SmsDataProvider.java b/src/main/java/fr/unix_experience/owncloud_sms/providers/SmsDataProvider.java
index 268328b..c882350 100644
--- a/src/main/java/fr/unix_experience/owncloud_sms/providers/SmsDataProvider.java
+++ b/src/main/java/fr/unix_experience/owncloud_sms/providers/SmsDataProvider.java
@@ -25,6 +25,7 @@ import android.net.Uri;
 import android.support.annotation.NonNull;
 import android.util.Log;
 
+import fr.unix_experience.owncloud_sms.enums.MailboxID;
 import fr.unix_experience.owncloud_sms.prefs.OCSMSSharedPrefs;
 
 public class SmsDataProvider extends ContentProvider {
@@ -84,6 +85,19 @@ public class SmsDataProvider extends ContentProvider {
         );
     }
 
+	public boolean messageExists(String address, String body, String date, MailboxID mb) {
+		Cursor c = query(Uri.parse(mb.getURI()), new String[] { "_id" },
+				"address = ? AND body = ? AND date = ?",
+				new String[] { address, body, date }, null);
+		if (c == null) {
+			return false;
+		}
+
+		boolean exists = c.getCount() > 0;
+		c.close();
+		return exists;
+	}
+
 	@Override
 	public Cursor query(@NonNull Uri uri, String[] projection, String selection,
 			String[] selectionArgs, String sortOrder) {
@@ -103,20 +117,14 @@ public class SmsDataProvider extends ContentProvider {
             selection = ((selection == null) || (selection.isEmpty())) ?
                     ("length(address) >= " + senderMinSize.toString()) :
                     ("length(address) >= " + senderMinSize.toString() + " AND " + selection);
-
-            Log.i(SmsDataProvider.TAG, "query: Minimum message length set to " + senderMinSize);
         }
 
         if (bulkLimit > 0) {
             if (sortOrder == null)
                 sortOrder = "date DESC";
             sortOrder += " LIMIT " + bulkLimit.toString();
-
-            Log.i(SmsDataProvider.TAG, "query: Bulk limit set to " + bulkLimit.toString());
         }
 
-        Log.i(SmsDataProvider.TAG, "query: selection set to " + selection);
-
         Cursor cursor = _context.getContentResolver().query(uri, projection, selection, selectionArgs, sortOrder);
 		if (cursor == null) {
 			return null;