diff --git a/main/document/upload.php b/main/document/upload.php
index d5ae884454..52400e3585 100755
--- a/main/document/upload.php
+++ b/main/document/upload.php
@@ -257,7 +257,7 @@ $form->addElement('hidden', 'curdirpath', $path);
 
 $courseQuota = format_file_size(DocumentManager::get_course_quota() - DocumentManager::documents_total_space());
 $label =
-    get_lang('MaxFileSize').': '.ini_get('upload_max_filesize').'<br/>'.
+    get_lang('MaxFileSize').': '.getIniMaxFileSizeInBytes(true).'<br/>'.
     get_lang('DocumentQuota').': '.$courseQuota;
 
 $form->addElement('BigUpload', 'file', [get_lang('File'), $label], ['id' => 'bigUploadFile', 'data-origin' => 'document']);
diff --git a/main/dropbox/dropbox_functions.inc.php b/main/dropbox/dropbox_functions.inc.php
index bcfdbebc11..5729c25430 100755
--- a/main/dropbox/dropbox_functions.inc.php
+++ b/main/dropbox/dropbox_functions.inc.php
@@ -540,7 +540,7 @@ function display_add_form($viewReceivedCategory, $viewSentCategory, $view, $id =
     $form->addElement('hidden', 'sec_token', $token);
     $form->addElement('hidden', 'origin', $origin);
     if ('add' == $action) {
-        $maxFileSize = api_get_setting('dropbox_max_filesize');
+        $maxFileSize = getIniMaxFileSizeInBytes();
         $form->addElement('hidden', 'MAX_FILE_SIZE', $maxFileSize);
         $form->addElement(
             'file',
@@ -1070,7 +1070,7 @@ function store_add_dropbox($file = [], $work = null)
         $dropbox_filetmpname = $file['tmp_name'];
 
         // check if the filesize does not exceed the allowed size.
-        $maxFileSize = api_get_setting('dropbox_max_filesize');
+        $maxFileSize = getIniMaxFileSizeInBytes();
         if ($dropbox_filesize <= 0 || $dropbox_filesize > $maxFileSize) {
             Display::addFlash(Display::return_message(get_lang('DropboxFileTooBig'), 'warning'));
 
diff --git a/main/forum/forumfunction.inc.php b/main/forum/forumfunction.inc.php
index 9e83594138..d28fdab9ce 100755
--- a/main/forum/forumfunction.inc.php
+++ b/main/forum/forumfunction.inc.php
@@ -749,7 +749,9 @@ function store_forum($values, $courseInfo = [], $returnId = false)
     // Forum images
     $has_attachment = false;
     $image_moved = true;
-    if (!empty($_FILES['picture']['name'])) {
+
+    $maxFileSize = getIniMaxFileSizeInBytes();
+    if (!empty($_FILES['picture']['name']) && !($maxFileSize > 0 && $_FILES['picture']['size'] > $maxFileSize)) {
         $upload_ok = process_uploaded_file($_FILES['picture']);
         $has_attachment = true;
     }
@@ -822,7 +824,7 @@ function store_forum($values, $courseInfo = [], $returnId = false)
         // Move groups from one group to another
         if (isset($values['group_forum'])) {
             $forumData = get_forums($values['forum_id']);
-            $currentGroupId = $forumData['forum_of_group'];
+            $currentGroupId = $forumData['forum_of_group'] ?? 0;
             if ($currentGroupId != $values['group_forum']) {
                 $threads = get_threads($values['forum_id']);
                 $toGroupId = 'NULL';
@@ -2868,16 +2870,22 @@ function store_thread(
     $upload_ok = 1;
     $has_attachment = false;
 
+    $maxFileSize = getIniMaxFileSizeInBytes();
     if (!empty($_FILES['user_upload']['name'])) {
-        $upload_ok = process_uploaded_file($_FILES['user_upload']);
-        $has_attachment = true;
+        $upload_ok = 0;
+        $has_attachment = false;
+        if ($maxFileSize > 0 && $_FILES['user_upload']['size'] <= $maxFileSize) {
+            $upload_ok = process_uploaded_file($_FILES['user_upload']);
+            $has_attachment = true;
+        }
     }
 
     if (!$upload_ok) {
         if ($showMessage) {
+            $errorUploadMessage = get_lang('FileSizeIsTooBig').' '.get_lang('MaxFileSize').' : '.getIniMaxFileSizeInBytes(true);
             Display::addFlash(
                 Display::return_message(
-                    get_lang('UplNoFileUploaded'),
+                    $errorUploadMessage,
                     'error',
                     false
                 )
@@ -3314,8 +3322,10 @@ function show_add_post_form($current_forum, $action, $form_values = [], $showPre
             null,
             ['id' => 'reply-add-attachment']
         );
+        $form->addRule('user_upload[]', get_lang('FileSizeIsTooBig').' '.get_lang('MaxFileSize').' : '.getIniMaxFileSizeInBytes(true), 'maxfilesize', getIniMaxFileSizeInBytes());
     } else {
-        $form->addFile('user_upload', get_lang('Attachment'));
+        $form->addFile('user_upload', get_lang('Attachment').' ('.get_lang('MaxFileSize').' : '.getIniMaxFileSizeInBytes(true).')');
+        $form->addRule('user_upload', get_lang('FileSizeIsTooBig').' '.get_lang('MaxFileSize').' : '.getIniMaxFileSizeInBytes(true), 'maxfilesize', getIniMaxFileSizeInBytes());
     }
 
     if ($giveRevision) {
@@ -3393,6 +3403,15 @@ function show_add_post_form($current_forum, $action, $form_values = [], $showPre
         }
     }
 
+    if (isset($_REQUEST['action']) && 'replythread' === $_REQUEST['action']) {
+        if (isset($_REQUEST['post_title'])) {
+            $defaults['post_title'] = $_REQUEST['post_title'];
+        }
+
+        if (isset($_REQUEST['post_text'])) {
+            $defaults['post_text'] = $_REQUEST['post_text'];
+        }
+    }
     $form->setDefaults(isset($defaults) ? $defaults : []);
 
     // The course admin can make a thread sticky (=appears with special icon and always on top).
@@ -3435,6 +3454,9 @@ function show_add_post_form($current_forum, $action, $form_values = [], $showPre
                         $threadId = $myThread->getIid();
                         Skill::saveSkills($form, ITEM_TYPE_FORUM_THREAD, $threadId);
                         $postId = $myThread->getThreadLastPost();
+                    } else {
+                        header('Location: '.api_request_uri());
+                        exit;
                     }
                     break;
                 case 'quote':
@@ -3849,6 +3871,29 @@ function store_reply($current_forum, $values, $courseId = 0, $userId = 0)
     $upload_ok = 1;
     $new_post_id = 0;
 
+    $errMessage = get_lang('UplNoFileUploaded').' '.get_lang('UplSelectFileFirst');
+    $maxFileSize = getIniMaxFileSizeInBytes();
+
+    if (!empty($_FILES['user_upload']['name'])) {
+        if (is_array($_FILES['user_upload']['name'])) {
+            $totalFileSize = 0;
+            for ($i = 0; $i < count($_FILES['user_upload']['name']); $i++) {
+                $totalFileSize += $_FILES['user_upload']['size'][$i];
+            }
+            if ($totalFileSize > $maxFileSize) {
+                $upload_ok = 0;
+                $errMessage = get_lang('FileSizeIsTooBig').' '.get_lang('MaxFileSize').' : '.getIniMaxFileSizeInBytes(true);
+            }
+        } else {
+            if ($maxFileSize > 0 && $_FILES['user_upload']['size'] <= $maxFileSize) {
+                $upload_ok = process_uploaded_file($_FILES['user_upload']);
+            } else {
+                $upload_ok = 0;
+                $errMessage = get_lang('FileSizeIsTooBig').' '.get_lang('MaxFileSize').' : '.getIniMaxFileSizeInBytes(true);
+            }
+        }
+    }
+
     if ($upload_ok) {
         // We first store an entry in the forum_post table.
         $new_post_id = Database::insert(
@@ -3954,10 +3999,12 @@ function store_reply($current_forum, $values, $courseId = 0, $userId = 0)
     } else {
         Display::addFlash(
             Display::return_message(
-                get_lang('UplNoFileUploaded').' '.get_lang('UplSelectFileFirst'),
+                $errMessage,
                 'error'
             )
         );
+
+        return false;
     }
 
     return $new_post_id;
@@ -5251,11 +5298,16 @@ function add_forum_attachment_file($file_comment, $last_id)
         }
     }
 
+    $maxFileSize = getIniMaxFileSizeInBytes();
     foreach ($filesData as $attachment) {
         if (empty($attachment['name'])) {
             continue;
         }
 
+        if ($maxFileSize > 0 && $attachment['size'] > $maxFileSize) {
+            continue;
+        }
+
         $upload_ok = process_uploaded_file($attachment);
 
         if (!$upload_ok) {
@@ -5347,13 +5399,17 @@ function edit_forum_attachment_file($file_comment, $post_id, $id_attach)
         }
     }
 
+    $maxFileSize = getIniMaxFileSizeInBytes();
     foreach ($filesData as $attachment) {
         if (empty($attachment['name'])) {
             continue;
         }
 
-        $upload_ok = process_uploaded_file($attachment);
+        if ($maxFileSize > 0 && $attachment['size'] > $maxFileSize) {
+            continue;
+        }
 
+        $upload_ok = process_uploaded_file($attachment);
         if (!$upload_ok) {
             continue;
         }
diff --git a/main/inc/lib/fileUpload.lib.php b/main/inc/lib/fileUpload.lib.php
index 69fa54b341..aea81fc7a5 100755
--- a/main/inc/lib/fileUpload.lib.php
+++ b/main/inc/lib/fileUpload.lib.php
@@ -2183,10 +2183,29 @@ function add_all_documents_in_folder_to_database(
  *
  * @return int
  */
-function getIniMaxFileSizeInBytes()
+function getIniMaxFileSizeInBytes($humanReadable = false, $checkMessageSetting = false)
 {
     $maxSize = 0;
-    if (preg_match('/^([0-9]+)([a-zA-Z]*)$/', ini_get('upload_max_filesize'), $matches)) {
+    $uploadMaxFilesize = ini_get('upload_max_filesize');
+    $fileSizeForTeacher = getFileUploadSizeLimitForTeacher();
+    if (!empty($fileSizeForTeacher)) {
+        $uploadMaxFilesize = $fileSizeForTeacher.'M';
+    }
+
+    if (empty($fileSizeForTeacher) && $checkMessageSetting) {
+        $uploadMaxFilesize = api_get_setting('message_max_upload_filesize'); // in bytes
+        if ($humanReadable) {
+            $uploadMaxFilesize = format_file_size($uploadMaxFilesize);
+        }
+
+        return $uploadMaxFilesize;
+    }
+
+    if ($humanReadable) {
+        return $uploadMaxFilesize;
+    }
+
+    if (preg_match('/^([0-9]+)([a-zA-Z]*)$/', $uploadMaxFilesize, $matches)) {
         // see http://www.php.net/manual/en/faq.using.php#faq.using.shorthandbytes
         switch (strtoupper($matches['2'])) {
             case 'G':
@@ -2206,3 +2225,19 @@ function getIniMaxFileSizeInBytes()
 
     return $maxSize;
 }
+
+/**
+ * Get the uploax max filesize from configuration.php for trainers in bytes.
+ *
+ * @return int
+ */
+function getFileUploadSizeLimitForTeacher()
+{
+    $size = 0;
+    $settingValue = (int) api_get_configuration_value('file_upload_size_limit_for_teacher'); // setting value in MB
+    if ($settingValue > 0 && (api_is_allowed_to_create_course() && !api_is_platform_admin())) {
+        $size = $settingValue;
+    }
+
+    return $size;
+}
diff --git a/main/inc/lib/formvalidator/Element/BigUpload.php b/main/inc/lib/formvalidator/Element/BigUpload.php
index 219cbef791..73f56a88bb 100644
--- a/main/inc/lib/formvalidator/Element/BigUpload.php
+++ b/main/inc/lib/formvalidator/Element/BigUpload.php
@@ -26,6 +26,7 @@ class BigUpload extends HTML_QuickForm_file
         $origin = $this->getAttribute('data-origin');
         $id = $this->getAttribute('id');
         $maxSize = getIniMaxFileSizeInBytes();
+        $errorUploadMessage = get_lang('FileSizeIsTooBig').' '.get_lang('MaxFileSize').' : '.getIniMaxFileSizeInBytes(true);
         $html = parent::toHtml();
         $html .= '<div id="'.$id.'-bigUploadProgressBarContainer">
             <div id="'.$id.'-bigUploadProgressBarFilled"></div>
@@ -75,6 +76,8 @@ class BigUpload extends HTML_QuickForm_file
                 bigUpload.settings.formParams = uploadForm.serialize();
                 //Max file size allowed
                 bigUpload.settings.maxFileSize = "'.$maxSize.'";
+                // Message error upload filesize
+                bigUpload.settings.errMessageFileSize = "'.$errorUploadMessage.'";
             }
         </script>';
 
diff --git a/main/inc/lib/formvalidator/FormValidator.class.php b/main/inc/lib/formvalidator/FormValidator.class.php
index c790985615..3474da9713 100755
--- a/main/inc/lib/formvalidator/FormValidator.class.php
+++ b/main/inc/lib/formvalidator/FormValidator.class.php
@@ -1820,7 +1820,9 @@ EOT;
         if (!empty($urlToRedirect)) {
             $redirectCondition = "window.location.replace('$urlToRedirect'); ";
         }
+        $maxFileSize = getIniMaxFileSizeInBytes();
         $icon = Display::return_icon('file_txt.gif');
+        $errorUploadMessage = get_lang('FileSizeIsTooBig').' '.get_lang('MaxFileSize').' : '.getIniMaxFileSizeInBytes(true);
         $this->addHtml("
         <script>
         $(function () {
@@ -1853,6 +1855,7 @@ EOT;
                     });
                 });
 
+            var maxFileSize = parseInt('".$maxFileSize."');
             var counter = 0,
                 total = 0;
             $('#".$inputName."').fileupload({
@@ -1885,19 +1888,39 @@ EOT;
 
             }).on('fileuploadadd', function (e, data) {
                 data.context = $('<div class=\"row\" />').appendTo('#files');
+                var errs = [];
                 $.each(data.files, function (index, file) {
-                    var node = $('<div class=\"col-sm-5 file_name\">').text(file.name);
-                    node.appendTo(data.context);
-                    var iconLoading = $('<div class=\"col-sm-3\">').html(
-                        $('<span id=\"image-loading'+index+'\"/>').html('".Display::return_icon('loading1.gif', get_lang('Uploading'), [], ICON_SIZE_MEDIUM)."')
-                    );
-                    $(data.context.children()[index]).parent().append(iconLoading);
-                    total++;
+                    // check size
+                    if (maxFileSize > 0 && data.files[index]['size'] > maxFileSize) {
+                        errs.push('".$errorUploadMessage."');
+                    } else {
+                        // array for all errors
+                        var node = $('<div class=\"col-sm-5 file_name\">').text(file.name);
+                        node.appendTo(data.context);
+                        var iconLoading = $('<div class=\"col-sm-3\">').html(
+                            $('<span id=\"image-loading'+index+'\"/>').html('".Display::return_icon('loading1.gif', get_lang('Uploading'), [], ICON_SIZE_MEDIUM)."')
+                        );
+                        $(data.context.children()[index]).parent().append(iconLoading);
+                        total++;
+                    }
                 });
+
+                // Output errors or submit data
+                if (errs.length > 0) {
+                    alert('".get_lang('AnErrorOccured')."' + errs.join(' '));
+                    return false;
+                } else {
+                    data.submit();
+                }
+
             }).on('fileuploadprocessalways', function (e, data) {
                 var index = data.index,
                     file = data.files[index],
                     node = $(data.context.children()[index]);
+
+                if (maxFileSize > 0 && data.files[index]['size'] > maxFileSize) {
+                    return false;
+                }
                 if (file.preview) {
                     data.context.prepend($('<div class=\"col-sm-4\">').html(file.preview));
                 } else {
diff --git a/main/inc/lib/formvalidator/Rule/MaxFileSize.php b/main/inc/lib/formvalidator/Rule/MaxFileSize.php
index 03ace54d2e..ac4b9f2da3 100644
--- a/main/inc/lib/formvalidator/Rule/MaxFileSize.php
+++ b/main/inc/lib/formvalidator/Rule/MaxFileSize.php
@@ -14,7 +14,7 @@ class HTML_QuickForm_Rule_MaxFileSize extends HTML_QuickForm_Rule
      *
      * @return bool
      */
-    public function validate($elementValue, $maxSize)
+    public function validate($elementValue, $maxSize = 0)
     {
         if (!empty($elementValue['error']) &&
             (UPLOAD_ERR_FORM_SIZE == $elementValue['error'] || UPLOAD_ERR_INI_SIZE == $elementValue['error'])
diff --git a/main/inc/lib/javascript/bigupload/js/bigUpload.js b/main/inc/lib/javascript/bigupload/js/bigUpload.js
index bd488fef69..a9b66a4fdb 100644
--- a/main/inc/lib/javascript/bigupload/js/bigUpload.js
+++ b/main/inc/lib/javascript/bigupload/js/bigUpload.js
@@ -49,7 +49,11 @@ function bigUpload () {
 		'maxFileSize': 2147483648,
 		
 		//CidReq
-		'cidReq': ''
+		'cidReq': '',
+
+		// Message error upload filesize
+		'errMessageFileSize': '',
+
 	};
 
 	//Upload specific variables
@@ -133,7 +137,8 @@ function bigUpload () {
 		//But this should be good enough to catch any immediate errors
 		var fileSize = this.uploadData.file.size;
 		if(fileSize > this.settings.maxFileSize) {
-			this.printResponse('The file you have chosen is too large.', true);
+			this.printResponse(this.settings.errMessageFileSize, true);
+			this.$(this.settings.submitButton).disabled = false;
 			return;
 		}
 
diff --git a/main/inc/lib/message.lib.php b/main/inc/lib/message.lib.php
index 831bc0325a..b0250fd208 100755
--- a/main/inc/lib/message.lib.php
+++ b/main/inc/lib/message.lib.php
@@ -666,13 +666,9 @@ class MessageManager
             );
 
             return false;
-        } elseif ($totalFileSize > (int) api_get_setting('message_max_upload_filesize')) {
-            $warning = sprintf(
-                get_lang('FilesSizeExceedsX'),
-                format_file_size(api_get_setting('message_max_upload_filesize'))
-            );
-
-            Display::addFlash(Display::return_message($warning, 'warning'));
+        } elseif ($totalFileSize > (int) getIniMaxFileSizeInBytes(false, true)) {
+            $warning = get_lang('FileSizeIsTooBig').' '.get_lang('MaxFileSize').' : '.getIniMaxFileSizeInBytes(true, true);
+            Display::addFlash(Display::return_message($warning, 'error'));
 
             return false;
         }
diff --git a/main/inc/lib/pear/HTML/QuickForm/RuleRegistry.php b/main/inc/lib/pear/HTML/QuickForm/RuleRegistry.php
index 8fa7a9682a..c4d4047d0f 100755
--- a/main/inc/lib/pear/HTML/QuickForm/RuleRegistry.php
+++ b/main/inc/lib/pear/HTML/QuickForm/RuleRegistry.php
@@ -148,9 +148,9 @@ class HTML_QuickForm_RuleRegistry
             'date' => 'HTML_QuickForm_Rule_Date',
             'compare_datetime_text' => 'HTML_QuickForm_Rule_CompareDateTimeText',
             'uploadedfile' => 'HTML_QuickForm_Rule_UploadFile',
-            'maxfilesize', 'HTML_QuickForm_Rule_MaxFileSize',
-            'mimetype', 'HTML_QuickForm_Rule_MimeType',
-            'filename', 'HTML_QuickForm_Rule_FileName',
+            'maxfilesize'=> 'HTML_QuickForm_Rule_MaxFileSize',
+            'mimetype' => 'HTML_QuickForm_Rule_MimeType',
+            'filename' => 'HTML_QuickForm_Rule_FileName',
             'validquestiontype' => 'HTML_QuickForm_Rule_QuestionType',
             'mintext' => 'Html_Quickform_Rule_MinText'
         );
diff --git a/main/install/configuration.dist.php b/main/install/configuration.dist.php
index 4ade7fd871..dda52412d9 100644
--- a/main/install/configuration.dist.php
+++ b/main/install/configuration.dist.php
@@ -2451,6 +2451,9 @@ INSERT INTO extra_field_options (field_id, option_value, display_text, priority,
 // Display the Portal News link in the admin page to session admin users
 //$_configuration['session_admin_access_system_announcement'] = false;
 
+// File upload size limit in MB for teachers (set to 1024 for 1GB, 5120 for 5GB, etc).
+//$_configuration['file_upload_size_limit_for_teacher'] = 0;
+
 // KEEP THIS AT THE END
 // -------- Custom DB changes
 // Add user activation by confirmation email
diff --git a/main/messages/new_message.php b/main/messages/new_message.php
index bbe6d9b781..35cc1b9205 100755
--- a/main/messages/new_message.php
+++ b/main/messages/new_message.php
@@ -119,6 +119,10 @@ function manageForm($default, $select_from_user_list = null, $sent_to = '', $tpl
         $onlyTeachers = true;
     }
 
+    if (isset($_SESSION['form_values'])) {
+        $default = $_SESSION['form_values'];
+    }
+
     $form = new FormValidator(
         'compose_message',
         null,
@@ -272,7 +276,7 @@ function manageForm($default, $select_from_user_list = null, $sent_to = '', $tpl
             get_lang('AddOneMoreFile').'</a></span>&nbsp;('.
             sprintf(
                 get_lang('MaximunFileSizeX'),
-                format_file_size(api_get_setting('message_max_upload_filesize'))
+                getIniMaxFileSizeInBytes(true, true)
             ).')'
         );
     }
@@ -301,6 +305,10 @@ function manageForm($default, $select_from_user_list = null, $sent_to = '', $tpl
         }
 
         if ($check) {
+            if (isset($_SESSION['form_values'])) {
+                unset($_SESSION['form_values']);
+            }
+
             $user_list = $default['users'];
             $file_comments = $_POST['legend'];
             $title = $default['title'];
@@ -349,6 +357,10 @@ function manageForm($default, $select_from_user_list = null, $sent_to = '', $tpl
                             'confirmation',
                             false
                         ));
+                    } else {
+                        $_SESSION['form_values'] = $default;
+                        header('Location: '.api_request_uri());
+                        exit;
                     }
                 }
                 MessageManager::cleanAudioMessage();
diff --git a/src/Chamilo/CoreBundle/Component/Editor/Driver/CourseDriver.php b/src/Chamilo/CoreBundle/Component/Editor/Driver/CourseDriver.php
index b71763d339..56c4d7c1d7 100644
--- a/src/Chamilo/CoreBundle/Component/Editor/Driver/CourseDriver.php
+++ b/src/Chamilo/CoreBundle/Component/Editor/Driver/CourseDriver.php
@@ -267,6 +267,16 @@ class CourseDriver extends Driver implements DriverInterface
         if ($this->allowToEdit()) {
             // upload file by elfinder.
             $size = filesize($tmpname);
+
+            // check the max filesize.
+            $maxFileSize = getIniMaxFileSizeInBytes();
+            if ($maxFileSize > 0 && $size > $maxFileSize) {
+                $errorUploadMessage = get_lang('FileSizeIsTooBig').' '.get_lang('MaxFileSize').' : '.getIniMaxFileSizeInBytes(true);
+                $this->addError($errorUploadMessage);
+
+                return false;
+            }
+
             $maxSpace = \DocumentManager::get_course_quota($this->connector->course['code']);
             // Check if there is enough space to save the file.
             if (!\DocumentManager::enough_space($size, $maxSpace)) {