diff --git a/README.md b/README.md
index 02ac436..97bc8e5 100644
--- a/README.md
+++ b/README.md
@@ -149,6 +149,10 @@ void DownloadManagerPro.StartQueueDownload(int downloadTaskPerTime, int sortType
 
 Example:
 ``` java
+int taskTokenOne   = dm.addTask("save_name", "http://www.site.com/video/ss.mp4",   false, false);
+int taskTokenTwo   = dm.addTask("save_name", "http://www.site.com/video/ss_1.mp4", false, false);
+int taskTokenThree = dm.addTask("save_name", "http://www.site.com/video/ss_2.mp4", false, false);
+
 try {
         dm.startQueueDownload(3, QueueSort.oldestFirst);
 
diff --git a/com/golshadi/majid/core/DownloadManagerPro.java b/com/golshadi/majid/core/DownloadManagerPro.java
index 1bae313..9cab682 100644
--- a/com/golshadi/majid/core/DownloadManagerPro.java
+++ b/com/golshadi/majid/core/DownloadManagerPro.java
@@ -352,6 +352,24 @@ public boolean delete(int token, boolean deleteTaskFile){
         return false;
     }
 
+    /**
+     * delete all uncompleted downloads tasks from db and files
+     */    
+    public void deleteAllUnCompleteds() {
+        List<Task> task           = tasksDataSource.allUnCompleteds();
+        if (task != null) {
+            for (Task tsk : task) {
+
+                List<Chunk> taskChunks =
+                        chunksDataSource.chunksRelatedTask(tsk.id);
+                for (Chunk chunk : taskChunks) {
+                    FileUtils.delete(tsk.save_address, String.valueOf(chunk.id));
+                    chunksDataSource.delete(chunk.id);
+                }
+                delete(tsk.id, true);
+            }
+        }
+    }
 
     /**
      * close db connection
diff --git a/com/golshadi/majid/core/mainWorker/QueueModerator.java b/com/golshadi/majid/core/mainWorker/QueueModerator.java
index bc182be..f136ae6 100644
--- a/com/golshadi/majid/core/mainWorker/QueueModerator.java
+++ b/com/golshadi/majid/core/mainWorker/QueueModerator.java
@@ -37,36 +37,43 @@ public QueueModerator(TasksDataSource tasksDataSource, ChunksDataSource chunksDa
         this.moderator = localModerator;
         this.moderator.setQueueObserver(this);
         this.listener = downloadManagerListener;
+	    
         this.downloadTaskPerTime = downloadPerTime;
+        if (tasks.size() < downloadPerTime) {
+            this.downloadTaskPerTime = tasks.size();
+        }
+	    
         this.uncompletedTasks = tasks;
         
-        downloaderList =
-                new HashMap<Integer, Thread>(downloadTaskPerTime);
+        downloaderList =new HashMap<>(downloadTaskPerTime);
     }
 
 
     public void startQueue() {
 
-    	if (uncompletedTasks != null) {
-	
-    		int location = 0;
-    		while (uncompletedTasks.size() > 0 && 
-    				!pauseFlag &&
-    				downloadTaskPerTime >= downloaderList.size()) {
-    			Task task = uncompletedTasks.get(location);
-    			Thread downloader =
-	                    new AsyncStartDownload(tasksDataSource, chunksDataSource, moderator, listener, task);
-	            
-	            downloaderList.put(task.id, downloader);
-	            uncompletedTasks.remove(location);
-	            
-	            downloader.start();
-	            
-	            
-				location++;
-			}
-    			        
-    	}
+        if (uncompletedTasks != null) {
+
+            int location = 0;
+            while (uncompletedTasks.size() > 0 &&
+                    !pauseFlag &&
+                    downloadTaskPerTime >= downloaderList.size()) {
+                try {
+                    Task task = uncompletedTasks.get(location);
+                    Thread downloader =
+                            new AsyncStartDownload(tasksDataSource, chunksDataSource, moderator, listener, task);
+
+                    downloaderList.put(task.id, downloader);
+                    uncompletedTasks.remove(location);
+
+                    downloader.start();
+
+                    location++;
+                } catch (IndexOutOfBoundsException e) {
+                    e.printStackTrace();
+                    Log.e("QueueModerator", e.getMessage());
+                }
+            }
+        }
     }
 
     public void wakeUp(int taskID){
diff --git a/com/golshadi/majid/database/TasksDataSource.java b/com/golshadi/majid/database/TasksDataSource.java
index 9ada974..2febf59 100644
--- a/com/golshadi/majid/database/TasksDataSource.java
+++ b/com/golshadi/majid/database/TasksDataSource.java
@@ -152,6 +152,31 @@ public Task getTaskInfo(int id) {
         return task;
     }
 
+    public List<Task> allUnCompleteds() {
+        List<Task> unCompleted = new ArrayList<>();
+
+        String query = "SELECT * FROM " + TABLES.TASKS
+                + " WHERE " + TASKS.COLUMN_STATE + "!=" + SqlString.Int(TaskStates.END);
+
+        Cursor cr = database.rawQuery(query, null);
+
+        if (cr != null) {
+            cr.moveToFirst();
+
+            while (!cr.isAfterLast()) {
+                Task task = new Task();
+                task.cursorToTask(cr);
+                unCompleted.add(task);
+
+                cr.moveToNext();
+            }
+
+            cr.close();
+        }
+
+        return unCompleted;
+    }
+
     public Task getTaskInfoWithName(String name) {
         String query = "SELECT * FROM "+TABLES.TASKS+" WHERE "+TASKS.COLUMN_NAME+"="+SqlString.String(name);
         Cursor cr = database.rawQuery(query, null);