diff --git a/backup/util/ui/backup_moodleform.class.php b/backup/util/ui/backup_moodleform.class.php
index f586d408da3..8fa06542f84 100644
--- a/backup/util/ui/backup_moodleform.class.php
+++ b/backup/util/ui/backup_moodleform.class.php
@@ -122,6 +122,8 @@ class backup_confirmation_form extends backup_moodleform {
         if (!array_key_exists('setting_root_filename', $errors)) {
             if (trim($data['setting_root_filename']) == '') {
                 $errors['setting_root_filename'] = get_string('errorfilenamerequired', 'backup');
+            } else if (strlen(trim($data['setting_root_filename'])) > 255) {
+                $errors['setting_root_filename'] = get_string('errorfilenametoolong', 'backup');
             } else if (!preg_match('#\.mbz$#i', $data['setting_root_filename'])) {
                 $errors['setting_root_filename'] = get_string('errorfilenamemustbezip', 'backup');
             }
diff --git a/lang/en/backup.php b/lang/en/backup.php
index 5e2e3d43ce7..46ed93e7b4a 100644
--- a/lang/en/backup.php
+++ b/lang/en/backup.php
@@ -140,6 +140,7 @@ $string['error_block_for_module_not_found'] = 'Orphan block instance (id: {$a->b
 $string['error_course_module_not_found'] = 'Orphan course module (id: {$a}) found. This module will not be backed up.';
 $string['errorcopyingbackupfile'] = "Failed to copy the backup file to the temporary folder before restoring.";
 $string['errorfilenamerequired'] = 'You must enter a valid filename for this backup';
+$string['errorfilenametoolong'] = 'The filename length you enter must be less than 255 characters';
 $string['errorfilenamemustbezip'] = 'The filename you enter must be a ZIP file and have the .mbz extension';
 $string['errorminbackup20version'] = 'This backup file has been created with one development version of Moodle backup ({$a->backup}). Minimum required is {$a->min}. Cannot be restored.';
 $string['errorinvalidformat'] = 'Unknown backup format';