diff --git a/admin/health.php b/admin/health.php
index c8a9a025455..66d7b67f957 100644
--- a/admin/health.php
+++ b/admin/health.php
@@ -619,107 +619,6 @@ class problem_000014 extends problem_base {
     }
 }
 
-class problem_000015 extends problem_base {
-    function title() {
-        return 'Question categories should belong to a valid context';
-    }
-    function exists() {
-        global $CFG;
-        return record_exists_sql("
-            SELECT qc.*, (SELECT COUNT(1) FROM {$CFG->prefix}question q WHERE q.category = qc.id) AS numquestions
-            FROM {$CFG->prefix}question_categories qc
-                LEFT JOIN {$CFG->prefix}context con ON qc.contextid = con.id
-            WHERE con.id IS NULL");
-    }
-    function severity() {
-        return SEVERITY_ANNOYANCE;
-    }
-    function description() {
-        global $CFG;
-        $problemcategories = get_records_sql("
-            SELECT qc.id, qc.name, qc.contextid, (SELECT COUNT(1) FROM {$CFG->prefix}question q WHERE q.category = qc.id) AS numquestions
-            FROM {$CFG->prefix}question_categories qc
-                LEFT JOIN {$CFG->prefix}context con ON qc.contextid = con.id
-            WHERE con.id IS NULL
-            ORDER BY numquestions DESC, qc.name");
-        $table = '<table><thead><tr><th>Cat id</th><th>Category name</th>' .
-        "<th>Context id</th><th>Num Questions</th></tr></thead><tbody>\n";
-        $maxnumquestions = 0;
-        if ($problemcategories) {
-            foreach ($problemcategories as $cat) {
-                $table .= "<tr><td>$cat->id/td><td>" . s($cat->name) . "</td><td>" .
-                $cat->contextid ."</td><td>$cat->numquestions</td></tr>\n";
-                if ($maxnumquestions < $cat->numquestions) {
-                    $maxnumquestions = $cat->numquestions;
-                }
-            }
-        }
-        $table .= '</tbody></table>';
-        return '<p>All question categories are linked to a context id, and, ' .
-        'the context they are linked to must exist. The following categories ' .
-        'belong to a non-existant category:</p>' . $table . '<p>Any of these ' .
-        'categories that contain no questions can just be deleted form the database. ' .
-        'Other categories will require more thought.</p>';
-    }
-    function solution() {
-        global $CFG;
-        return '<p>You can delete the empty categories by executing the following SQL:</p><pre>
-DELETE FROM ' . $CFG->prefix . 'question_categories
-WHERE
-    NOT EXIST (SELECT * FROM ' . $CFG->prefix . 'question q WHERE q.category = qc.id)
-AND NOT EXIST (SELECT * FROM ' . $CFG->prefix . 'context context WHERE qc.contextid = con.id)
-        </pre><p>Any remaining categories that contain questions will require more thought. ' .
-        'People in the <a href="http://moodle.org/mod/forum/view.php?f=121">Quiz forum</a> may be able to help.</p>';
-    }
-}
-
-class problem_000016 extends problem_base {
-    function title() {
-        return 'Question categories should belong to the same context as their parent';
-    }
-    function exists() {
-        global $CFG;
-        return record_exists_sql("
-            SELECT parent_qc.id AS parent, child_qc.id AS child, child_qc.contextid
-            FROM {$CFG->prefix}question_categories child_qc
-                JOIN {$CFG->prefix}question_categories parent_qc ON child_qc.parent = parent_qc.id
-            WHERE child_qc.contextid <> parent_qc.contextid");
-    }
-    function severity() {
-        return SEVERITY_ANNOYANCE;
-    }
-    function description() {
-        global $CFG;
-        $problemcategories = get_records_sql("
-            SELECT
-                parent_qc.id AS parentid, parent_qc.name AS parentname, parent_qc.contextid AS parentcon,
-                child_qc.id AS childid, child_qc.name AS childname, child_qc.contextid AS childcon
-            FROM {$CFG->prefix}question_categories child_qc
-                JOIN {$CFG->prefix}question_categories parent_qc ON child_qc.parent = parent_qc.id
-            WHERE child_qc.contextid <> parent_qc.contextid");
-        $table = '<table><thead><tr><th colspan="3">Child category</th><th colspan="3">Parent category</th></tr><tr>' .
-        '<th>Id</th><th>Name</th><th>Context id</th>' .
-        '<th>Id</th><th>Name</th><th>Context id</th>' .
-        "</tr></thead><tbody>\n";
-        if ($problemcategories) {
-            foreach ($problemcategories as $cat) {
-                $table .= "<tr><td>$cat->childid/td><td>" . s($cat->childname) .
-                "</td><td>$cat->childcon</td><td>$cat->parentid/td><td>" . s($cat->parentname) .
-                "</td><td>$cat->parentcon</td></tr>\n";
-            }
-        }
-        $table .= '</tbody></table>';
-        return '<p>When one question category is the parent of another, then they ' .
-        'should both belong to the same context. This is not true for the following categories:</p>' .
-        $table;
-    }
-    function solution() {
-        return '<p>An automated solution is difficult. It depends whether the ' .
-        'parent or child category is in the wrong pace.' .
-        'People in the <a href="http://moodle.org/mod/forum/view.php?f=121">Quiz forum</a> may be able to help.</p>';
-    }
-}
-
 class problem_00000x extends problem_base {
     function title() {
         return '';