diff --git a/lib/db/upgrade.php b/lib/db/upgrade.php
index cc0cc3620ea..73d48f8f12e 100644
--- a/lib/db/upgrade.php
+++ b/lib/db/upgrade.php
@@ -1187,5 +1187,14 @@ function xmldb_main_upgrade($oldversion) {
         upgrade_main_savepoint(true, 2012062507.01);
     }
 
+    if ($oldversion < 2012062507.06) {
+        // Clean up old tokens which haven't been deleted.
+        $DB->execute("DELETE FROM {user_private_key} WHERE NOT EXISTS
+                         (SELECT 'x' FROM {user} WHERE deleted = 0 AND id = userid)");
+
+        // Main savepoint reached.
+        upgrade_main_savepoint(true, 2012062507.06);
+    }
+
     return true;
 }
diff --git a/lib/moodlelib.php b/lib/moodlelib.php
index 277b4967212..a1f8a0a74fe 100644
--- a/lib/moodlelib.php
+++ b/lib/moodlelib.php
@@ -4031,6 +4031,9 @@ function delete_user(stdClass $user) {
     // unauthorise the user for all services
     $DB->delete_records('external_services_users', array('userid'=>$user->id));
 
+    // Remove users private keys.
+    $DB->delete_records('user_private_key', array('userid' => $user->id));
+
     // force logout - may fail if file based sessions used, sorry
     session_kill_user($user->id);
 
diff --git a/version.php b/version.php
index 880310bb993..bc166b2fc99 100644
--- a/version.php
+++ b/version.php
@@ -29,8 +29,7 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-
-$version  = 2012062507.05;              // YYYYMMDD      = weekly release date of this DEV branch
+$version  = 2012062507.06;              // YYYYMMDD      = weekly release date of this DEV branch
                                         //         RR    = release increments - 00 in DEV branches
                                         //           .XX = incremental changes