diff --git a/lib/tests/user_menu_test.php b/lib/tests/user_menu_test.php
index dbabd2ba2f4..af9335e10da 100644
--- a/lib/tests/user_menu_test.php
+++ b/lib/tests/user_menu_test.php
@@ -38,6 +38,14 @@ class core_user_menu_testcase extends advanced_testcase {
             array('-----', 0, 0),
             array('_____', 0, 0),
             array('test', 0, 0),
+            array('#Garbage#', 0, 0),
+
+            // These are valid but have an invalid string identifiers or components. They will still produce a menu
+            // item, and no exception should be thrown.
+            array('#my1files,moodle|/user/files.php|download', 1, 0),
+            array('#my1files,moodleakjladf|/user/files.php|download', 1, 0),
+            array('#my1files,a/b|/user/files.php|download', 1, 0),
+            array('#my1files,#b|/user/files.php|download', 1, 0),
 
             // These are unusual, but valid and will generate a menu entry (no filler).
             array('-|-|-|-', 1, 0),
diff --git a/user/lib.php b/user/lib.php
index 0689e18a178..4ba6d6119f2 100644
--- a/user/lib.php
+++ b/user/lib.php
@@ -657,9 +657,13 @@ function user_convert_text_to_menu_items($text, $page) {
         // Name processing.
         $namebits = explode(',', $bits[0], 2);
         if (count($namebits) == 2) {
-            // Treat this as a language string.
-            $child->title = get_string($namebits[0], $namebits[1]);
-        } else {
+            // Check the validity of the identifier part of the string.
+            if (clean_param($namebits[0], PARAM_STRINGID) !== '') {
+                // Treat this as a language string.
+                $child->title = get_string($namebits[0], $namebits[1]);
+            }
+        }
+        if (empty($child->title)) {
             // Use it as is, don't even clean it.
             $child->title = $bits[0];
         }