diff --git a/db/migrations/5.1.46_fix_for_biest2591.php b/db/migrations/5.1.46_fix_for_biest2591.php
new file mode 100644
index 0000000000000000000000000000000000000000..4617ff9d10558beb222ff728142a915499baa2ba
--- /dev/null
+++ b/db/migrations/5.1.46_fix_for_biest2591.php
@@ -0,0 +1,20 @@
+<?php
+final class FixForBiest2591 extends Migration
+{
+    protected function up()
+    {
+        $query = "DELETE `tools_activated`
+                  FROM `tools_activated`
+                  JOIN `seminare` ON `range_id` = `Seminar_id`
+                  WHERE `seminare`.`status` IN (
+                    SELECT `id`
+                    FROM `sem_classes`
+                    WHERE `studygroup_mode` = 1
+                  ) AND `plugin_id` IN (
+                    SELECT `pluginid`
+                    FROM `plugins`
+                    WHERE `pluginclassname` = 'CoreParticipants'
+                  )";
+        DBManager::get()->exec($query);
+    }
+}
diff --git a/lib/classes/SemClass.class.php b/lib/classes/SemClass.class.php
index 0fee25341cf32798f25222a656da03265553206f..36bfd70d631562eddc3e28f7396dc9ecec82ba6c 100644
--- a/lib/classes/SemClass.class.php
+++ b/lib/classes/SemClass.class.php
@@ -44,7 +44,6 @@ class SemClass implements ArrayAccess
     static protected $studygroup_forbidden_modules = [
         'CoreAdmin',
         'CoreParticipants',
-        'CoreSchedule'
     ];
 
     static protected $sem_classes = null;