diff --git a/src/wp-includes/js/plupload/handlers.js b/src/wp-includes/js/plupload/handlers.js
index 5ee7a43779..cadcc23d08 100644
--- a/src/wp-includes/js/plupload/handlers.js
+++ b/src/wp-includes/js/plupload/handlers.js
@@ -285,7 +285,7 @@ function uploadError(fileObj, errorCode, message, uploader) {
 			wpFileError(fileObj, pluploadL10n.upload_failed);
 			break;
 		case plupload.FILE_EXTENSION_ERROR:
-			wpFileError(fileObj, pluploadL10n.invalid_filetype);
+			wpFileExtensionError( uploader, file, pluploadL10n.invalid_filetype );
 			break;
 		case plupload.FILE_SIZE_ERROR:
 			uploadSizeError(uploader, fileObj);
@@ -340,6 +340,11 @@ function uploadSizeError( up, file, over100mb ) {
 	up.removeFile(file);
 }
 
+function wpFileExtensionError( up, file, message ) {
+	jQuery('#media-items').append('<div id="media-item-' + file.id + '" class="media-item error"><p>' + message + '</p></div>');
+	up.removeFile(file);
+}
+
 jQuery(document).ready(function($){
 	$('.media-upload-form').bind('click.uploader', function(e) {
 		var target = $(e.target), tr, c;
diff --git a/src/wp-includes/media.php b/src/wp-includes/media.php
index dfb4812241..3e860dc4bc 100644
--- a/src/wp-includes/media.php
+++ b/src/wp-includes/media.php
@@ -2918,7 +2918,7 @@ function _wp_image_editor_choose( $args = array() ) {
 }
 
 /**
- * Prints default plupload arguments.
+ * Prints default Plupload arguments.
  *
  * @since 3.4.0
  */
@@ -2930,6 +2930,11 @@ function wp_plupload_default_settings() {
 		return;
 
 	$max_upload_size = wp_max_upload_size();
+	$allowed_extensions = array_keys( get_allowed_mime_types() );
+	$extensions = array();
+	foreach ( $allowed_extensions as $extension ) {
+		$extensions = array_merge( $extensions, explode( '|', $extension ) );
+	}
 
 	$defaults = array(
 		'runtimes'            => 'html5,flash,silverlight,html4',
@@ -2939,6 +2944,7 @@ function wp_plupload_default_settings() {
 		'silverlight_xap_url' => includes_url( 'js/plupload/plupload.silverlight.xap' ),
 		'filters' => array(
 			'max_file_size'   => $max_upload_size . 'b',
+			'mime_types'      => array( array( 'extensions' => implode( ',', $extensions ) ) ),
 		),
 	);