diff --git a/main/admin/course_user_import.php b/main/admin/course_user_import.php
index bbf91221f7..aa8c79fe9a 100755
--- a/main/admin/course_user_import.php
+++ b/main/admin/course_user_import.php
@@ -72,9 +72,17 @@ function save_data($users_courses)
     $course_user_table = Database::get_main_table(TABLE_MAIN_COURSE_USER);
     $csv_data = array();
     $inserted_in_course = array();
-
+    $courseListCache = [];
+    $courseListById = [];
     foreach ($users_courses as $user_course) {
-        $csv_data[$user_course['UserName']][$user_course['CourseCode']] = $user_course['Status'];
+        if (!in_array($user_course['CourseCode'], array_keys($courseListCache))) {
+            $courseInfo = api_get_course_info($user_course['CourseCode']);
+            $courseListCache[$user_course['CourseCode']] = $courseInfo;
+        } else {
+            $courseInfo = $courseListCache[$user_course['CourseCode']];
+        }
+        $courseListById[$courseInfo['real_id']] = $courseInfo;
+        $csv_data[$user_course['UserName']][$courseInfo['real_id']] = $user_course['Status'];
     }
 
     foreach ($csv_data as $username => $csv_subscriptions) {
@@ -96,33 +104,24 @@ function save_data($users_courses)
 
         if ($_POST['subscribe']) {
             foreach ($to_subscribe as $courseId) {
-                $courseInfo = api_get_course_info_by_id($courseId);
-                $course_code = $courseInfo['code'];
+                $courseInfo = $courseListById[$courseId];
+                $courseCode = $courseInfo['code'];
 
-                if (CourseManager :: course_exists($course_code)) {
                     CourseManager::subscribe_user(
                         $user_id,
-                        $course_code,
-                        $csv_subscriptions[$course_code]
+                        $courseCode,
+                        $csv_subscriptions[$courseId]
                     );
-                    $course_info = CourseManager::get_course_information($course_code);
-                    $inserted_in_course[$course_code] = $course_info['title'];
-                    $inserted_in_course[$course_info['code']] = $course_info['title'];
-                }
+                    $inserted_in_course[$courseInfo['code']] = $courseInfo['title'];
+
             }
         }
 
         if ($_POST['unsubscribe']) {
             foreach ($to_unsubscribe as $courseId) {
-                $courseInfo = api_get_course_info_by_id($courseId);
-                $course_code = $courseInfo['code'];
-
-                if (CourseManager :: course_exists($course_code)) {
-                    CourseManager::unsubscribe_user($user_id, $course_code);
-                    $course_info = CourseManager::get_course_information($course_code);
-                    CourseManager::unsubscribe_user($user_id, $course_code);
-                    $inserted_in_course[$course_info['code']] = $course_info['title'];
-                }
+                $courseInfo = $courseListById[$courseId];
+                $courseCode = $courseInfo['code'];
+                CourseManager::unsubscribe_user($user_id, $courseCode);
             }
         }
     }
@@ -189,10 +188,11 @@ if ($form->validate()) {
             $warn = get_lang('ErrorsWhenImportingFile');
         }
 
+        Display::addFlash(Display::return_message($warn));
+
         Security::clear_token();
         $tok = Security::get_token();
-        Display::addFlash(Display::return_message($warn));
-        header('Location: user_list.php?sec_token='.$tok);
+        header('Location: '.api_get_self());
         exit();
     }
 }
diff --git a/main/inc/lib/formvalidator/FormValidator.class.php b/main/inc/lib/formvalidator/FormValidator.class.php
index 012f88bd26..65dd4c94d2 100755
--- a/main/inc/lib/formvalidator/FormValidator.class.php
+++ b/main/inc/lib/formvalidator/FormValidator.class.php
@@ -1333,14 +1333,14 @@ EOT;
             var uploadButton = $('<button/>')
                 .addClass('btn btn-primary')
                 .prop('disabled', true)
-                .text('".get_lang('Loading')."')
+                .text('".addslashes(get_lang('Loading'))."')
                 .on('click', function () {
                     var \$this = $(this),
                     data = \$this.data();
 
                     \$this
                         .off('click')
-                        .text('".get_lang('Cancel')."')
+                        .text('".addslashes(get_lang('Cancel'))."')
                         .on('click', function () {
                             \$this.remove();
                             data.abort();
diff --git a/main/inc/lib/groupmanager.lib.php b/main/inc/lib/groupmanager.lib.php
index e1fd95f5b4..2e9a22c3b7 100755
--- a/main/inc/lib/groupmanager.lib.php
+++ b/main/inc/lib/groupmanager.lib.php
@@ -401,12 +401,13 @@ class GroupManager
         self::unsubscribe_all_users($group_ids);
         self::unsubscribe_all_tutors($group_ids);
 
-        $sql = "SELECT id, secret_directory, session_id
+        $sql = "SELECT id, iid, secret_directory, session_id
                 FROM $group_table
                 WHERE c_id = $course_id AND id IN (".implode(' , ', $group_ids).")";
         $db_result = Database::query($sql);
 
         while ($group = Database::fetch_object($db_result)) {
+            $groupId = $group->iid;
             // move group-documents to garbage
             $source_directory = api_get_path(SYS_COURSE_PATH).$course_info['path']."/document".$group->secret_directory;
             // File to renamed
@@ -426,22 +427,22 @@ class GroupManager
                     }
                 }
             }
-        }
 
-        $sql = "DELETE FROM ".$forum_table."
-                WHERE c_id = $course_id AND forum_of_group IN ('".implode("' , '", $group_ids)."')";
-        Database::query($sql);
+            $sql = "DELETE FROM $forum_table
+                    WHERE c_id = $course_id AND forum_of_group = $groupId ";
+            Database::query($sql);
 
-        // Delete item properties of this group.
-        $itemPropertyTable = Database::get_course_table(TABLE_ITEM_PROPERTY);
-        $sql = "DELETE FROM ".$itemPropertyTable."
-                WHERE c_id = $course_id AND to_group_id IN ('".implode("' , '", $group_ids)."')";
-        Database::query($sql);
+            // Delete item properties of this group.
+            $itemPropertyTable = Database::get_course_table(TABLE_ITEM_PROPERTY);
+            $sql = "DELETE FROM $itemPropertyTable
+                    WHERE c_id = $course_id AND to_group_id = $groupId ";
+            Database::query($sql);
 
-        // delete the groups
-        $sql = "DELETE FROM ".$group_table."
-                WHERE c_id = $course_id AND id IN ('".implode("' , '", $group_ids)."')";
-        Database::query($sql);
+            // delete the groups
+            $sql = "DELETE FROM $group_table
+                    WHERE c_id = $course_id AND iid = $groupId ";
+            Database::query($sql);
+        }
 
         return true;
     }
diff --git a/main/install/configuration.dist.php b/main/install/configuration.dist.php
index 08b068aa5f..008d52b373 100755
--- a/main/install/configuration.dist.php
+++ b/main/install/configuration.dist.php
@@ -242,5 +242,8 @@ $_configuration['system_stable'] = NEW_VERSION_STABLE;
 //$_configuration['packager'] = 'chamilo';
 // If true exercises added in LP can be modified.
 //$_configuration['force_edit_exercise_in_lp'] = false;
+// to reflect their packaging method. The default value is 'chamilo'. This will
+// be reflected on the https://version.chamilo.org/stats page in the future.
+//$_configuration['packager'] = 'chamilo';
 // List of driver to plugin in ckeditor
-//$_configuration['editor_driver_list'] = ['PersonalDriver', 'CourseDriver'];
\ No newline at end of file
+//$_configuration['editor_driver_list'] = ['PersonalDriver', 'CourseDriver'];