diff --git a/lib/moodlelib.php b/lib/moodlelib.php
index 5c89fc35bb4..37abbaa816a 100644
--- a/lib/moodlelib.php
+++ b/lib/moodlelib.php
@@ -1957,6 +1957,11 @@ function require_login($courseorid=0, $autologinguest=true, $cm=null) {
     /// If the user is a guest then treat them according to the course policy about guests
 
         if (has_capability('moodle/legacy:guest', $COURSE->context, NULL, false)) {
+            if (has_capability('moodle/site:doanything', $sysctx)) {
+                // administrators must be able to access any course - even if somebody gives them guest access
+                return true;
+            }
+
             switch ($COURSE->guest) {    /// Check course policy about guest access
 
                 case 1:    /// Guests always allowed