diff --git a/lib/form/filepicker.js b/lib/form/filepicker.js
index 2a84f0329e1..e27d4af5c38 100644
--- a/lib/form/filepicker.js
+++ b/lib/form/filepicker.js
@@ -1,19 +1,34 @@
 
 M.form_filepicker = {};
-
+M.form_filepicker.Y = null;
+M.form_filepicker.instances = [];
 
 M.form_filepicker.callback = function(params) {
     var html = '<a href="'+params['url']+'">'+params['file']+'</a>';
     document.getElementById('file_info_'+params['client_id']).innerHTML = html;
+    //When file is added then set status of global variable to true
+    var elementname = M.core_filepicker.instances[params['client_id']].options.elementname;
+    M.form_filepicker.instances[elementname].fileadded = true;
+    //generate event to indicate changes which will be used by disable if or validation code
+    M.form_filepicker.Y.one('#id_'+elementname).simulate('change');
 };
 
 /**
  * This fucntion is called for each file picker on page.
  */
 M.form_filepicker.init = function(Y, options) {
+    //Keep reference of YUI, so that it can be used in callback.
+    M.form_filepicker.Y = Y;
+
+    //For client side validation, initialize file status for this filepicker
+    M.form_filepicker.instances[options.elementname] = {};
+    M.form_filepicker.instances[options.elementname].fileadded = false;
+
+    //Set filepicker callback
     options.formcallback = M.form_filepicker.callback;
+
     if (!M.core_filepicker.instances[options.client_id]) {
-        M.core_filepicker.init(Y, options); 
+        M.core_filepicker.init(Y, options);
     }
     Y.on('click', function(e, client_id) {
         e.preventDefault();
diff --git a/lib/form/filepicker.php b/lib/form/filepicker.php
index 26f57fc53b1..cfa491d3366 100644
--- a/lib/form/filepicker.php
+++ b/lib/form/filepicker.php
@@ -79,6 +79,7 @@ class MoodleQuickForm_filepicker extends HTML_QuickForm_input {
         $args->maxbytes = $this->_options['maxbytes'];
         $args->context = $PAGE->context;
         $args->buttonname = $elname.'choose';
+        $args->elementname = $elname;
 
         $html = $this->_getTabs();
         $fp = new file_picker($args);
@@ -87,7 +88,7 @@ class MoodleQuickForm_filepicker extends HTML_QuickForm_input {
         $html .= $OUTPUT->render($fp);
         $html .= '<input type="hidden" name="'.$elname.'" id="'.$id.'" value="'.$draftitemid.'" class="filepickerhidden"/>';
 
-        $module = array('name'=>'form_filepicker', 'fullpath'=>'/lib/form/filepicker.js', 'requires'=>array('core_filepicker'));
+        $module = array('name'=>'form_filepicker', 'fullpath'=>'/lib/form/filepicker.js', 'requires'=>array('core_filepicker', 'node', 'node-event-simulate'));
         $PAGE->requires->js_init_call('M.form_filepicker.init', array($fp->options), true, $module);
 
         $nonjsfilepicker = new moodle_url('/repository/draftfiles_manager.php', array(
diff --git a/lib/form/form.js b/lib/form/form.js
index 140a47502e3..0b69586b760 100644
--- a/lib/form/form.js
+++ b/lib/form/form.js
@@ -277,7 +277,17 @@ M.form.initFormDependencies = function(Y, formid, dependencies) {
                     } else if (this.getAttribute('type').toLowerCase() == 'checkbox' && !Y.Node.getDOMNode(this).checked) {
                         return;
                     }
-                    lock = lock || this.get('value') == value;
+                    //check for filepicker status
+                    if (this.getAttribute('class').toLowerCase() == 'filepickerhidden') {
+                        var elementname = this.getAttribute('name');
+                        if (elementname && M.form_filepicker.instances[elementname].fileadded) {
+                            lock = false;
+                        } else {
+                            lock = true;
+                        }
+                    } else {
+                        lock = lock || this.get('value') == value;
+                    }
                 });
                 return {
                     lock : lock,
@@ -298,7 +308,17 @@ M.form.initFormDependencies = function(Y, formid, dependencies) {
                     } else if (this.getAttribute('type').toLowerCase() == 'checkbox' && !Y.Node.getDOMNode(this).checked) {
                         return;
                     }
-                    lock = lock || this.get('value') != value;
+                    //check for filepicker status
+                    if (this.getAttribute('class').toLowerCase() == 'filepickerhidden') {
+                        var elementname = this.getAttribute('name');
+                        if (elementname && M.form_filepicker.instances[elementname].fileadded) {
+                            lock = true;
+                        } else {
+                            lock = false;
+                        }
+                    } else {
+                        lock = lock || this.get('value') != value;
+                    }
                 });
                 return {
                     lock : lock,
diff --git a/lib/formslib.php b/lib/formslib.php
index 7ca16279394..cee1aafaeda 100644
--- a/lib/formslib.php
+++ b/lib/formslib.php
@@ -2327,7 +2327,7 @@ class MoodleQuickForm_Renderer extends HTML_QuickForm_Renderer_Tableless{
         if (!$form->isFrozen()) {
             $args = $form->getLockOptionObject();
             if (count($args[1]) > 0) {
-                $PAGE->requires->js_init_call('M.form.initFormDependencies', $args, false, moodleform::get_js_module());
+                $PAGE->requires->js_init_call('M.form.initFormDependencies', $args, true, moodleform::get_js_module());
             }
         }
     }