Index: src/wp-includes/formatting.php
===================================================================
--- src/wp-includes/formatting.php	(revision 27454)
+++ src/wp-includes/formatting.php	(working copy)
@@ -888,6 +888,7 @@
 	 * @param string $filename_raw  Filename as it was passed into sanitize_file_name().
 	 */
 	$special_chars = apply_filters( 'sanitize_file_name_chars', $special_chars, $filename_raw );
+	$filename = preg_replace( "#\x{00a0}#siu", ' ', $filename );
 	$filename = str_replace($special_chars, '', $filename);
 	$filename = preg_replace('/[\s-]+/', '-', $filename);
 	$filename = trim($filename, '.-_');