diff --git a/VERSION b/VERSION
index e9344b5..44df9c6 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.3.95-beta
+0.3.96-beta
diff --git a/public/js/core.js b/public/js/core.js
index dd196e8..46f62bd 100644
--- a/public/js/core.js
+++ b/public/js/core.js
@@ -2,7 +2,7 @@
 "use strict";
 /* version — shown until /api/version resolves (or if the fetch fails, e.g. offline).
    Kept in sync by hand with the VERSION file at the repo root on every release. */
-const VERSION = "0.3.95-beta";
+const VERSION = "0.3.96-beta";
 (function(){
   const tag = document.getElementById("verTag");
   tag.textContent = "v"+VERSION;
diff --git a/src/api.js b/src/api.js
index d7a71d4..cfb132c 100644
--- a/src/api.js
+++ b/src/api.js
@@ -651,6 +651,47 @@ export default async function api(app) {
     return { ok: true };
   });
 
+  // Een gebruiker en al z'n afhankelijke gegevens in één transactie verwijderen.
+  // We rekenen NIET op ON DELETE CASCADE: sommige (oudere) databases hebben een
+  // foreign key die dat mist, waardoor DELETE FROM users een 500 "serverfout"
+  // geeft. Door de afhankelijke rijen eerst zelf te verwijderen werkt het
+  // ongeacht de exacte FK-instelling. Migratie 015 herstelt de FK's daarnaast
+  // structureel; dit is het vangnet dat sowieso werkt.
+  const deleteUserFully = async (userId) => {
+    const client = await pool.connect();
+    try {
+      await client.query('BEGIN');
+      // bewuste SET NULL: wie iets in het CMS wijzigde blijft die inhoud houden
+      await client.query('UPDATE site_content SET updated_by = NULL WHERE updated_by = $1', [userId]);
+      // eerst de klas/school van de gebruiker zelf lossnijden zodat triggers op
+      // eventuele resten niet in de weg zitten
+      const dependents = [
+        'DELETE FROM sessions WHERE user_id = $1',
+        'DELETE FROM user_roles WHERE user_id = $1',
+        'DELETE FROM class_teachers WHERE user_id = $1',
+        'DELETE FROM assignments WHERE pupil_id = $1 OR teacher_id = $1',
+        'DELETE FROM progress_events WHERE pupil_id = $1 OR teacher_id = $1',
+        'DELETE FROM parent_children WHERE parent_id = $1 OR pupil_id = $1',
+        'DELETE FROM school_link_requests WHERE parent_id = $1 OR pupil_id = $1',
+        'DELETE FROM user_data_versions WHERE user_id = $1',
+        'DELETE FROM shared_library WHERE owner_id = $1',
+        'DELETE FROM image_assets WHERE owner_id = $1',
+        'DELETE FROM image_folders WHERE owner_id = $1',
+        'DELETE FROM image_themes WHERE owner_id = $1',
+        'DELETE FROM boards WHERE owner_id = $1',
+        'DELETE FROM folders WHERE owner_id = $1',
+      ];
+      for (const sql of dependents) await client.query(sql, [userId]);
+      await client.query('DELETE FROM users WHERE id = $1', [userId]);
+      await client.query('COMMIT');
+    } catch (e) {
+      await client.query('ROLLBACK').catch(() => {});
+      throw e;
+    } finally {
+      client.release();
+    }
+  };
+
   app.delete('/admin/users/:id', async (req, reply) => {
     need(req, reply, PERMISSIONS['users.manage']);
     const r = await pool.query('SELECT * FROM users WHERE id = $1', [req.params.id]);
@@ -663,13 +704,13 @@ export default async function api(app) {
       return fail(reply, 403, 'groepsleiding beheert alleen leerlingen uit eigen klassen');
     if (u.role === 'super' && !req.user.allRoles.includes('super')) return fail(reply, 403, 'geen rechten');
     try {
-      await pool.query('DELETE FROM users WHERE id = $1', [u.id]);
+      await deleteUserFully(u.id);
     } catch (e) {
-      // 23503 = foreign_key_violation: een gekoppelde tabel is (nog) niet
-      // ON DELETE CASCADE. Migratie 015 herstelt dat; tot die tijd een
-      // begrijpelijke melding i.p.v. een kale "serverfout".
-      if (e.code === '23503') return fail(reply, 409, 'verwijderen mislukt: er hangen nog gekoppelde gegevens aan dit account');
-      throw e;
+      // Zou niet meer moeten voorkomen (alle afhankelijke rijen zijn hierboven
+      // al weggehaald), maar als het tóch faalt geven we de echte reden mee i.p.v.
+      // een kale "serverfout", zodat de oorzaak zichtbaar is.
+      req.log.error({ err: e }, 'verwijderen gebruiker mislukt');
+      return fail(reply, 409, `verwijderen mislukt: ${e.detail || e.message}`);
     }
     return { ok: true };
   });
diff --git a/test/schools.test.js b/test/schools.test.js
index 711cec1..a9430a6 100644
--- a/test/schools.test.js
+++ b/test/schools.test.js
@@ -8,16 +8,19 @@ import { readFile } from 'node:fs/promises';
 
 function makeApp(user, targetUser) {
   const calls = [];
+  const query = async (sql, params = []) => {
+    calls.push({ sql, params });
+    if (sql.includes('FROM sessions s JOIN users u')) return { rows: [user] };
+    if (sql.includes('FROM user_roles')) return { rows: [] };
+    if (sql.startsWith('UPDATE schools SET name')) return { rows: [{ id: params[1], name: params[0] }] };
+    if (sql.startsWith('SELECT * FROM classes WHERE id')) return { rows: [{ id: 100, school_id: 2, name: 'Groep 4' }] };
+    if (sql.startsWith('SELECT * FROM users WHERE id') && targetUser) return { rows: [targetUser] };
+    return { rows: [] };
+  };
   const pool = {
-    async query(sql, params = []) {
-      calls.push({ sql, params });
-      if (sql.includes('FROM sessions s JOIN users u')) return { rows: [user] };
-      if (sql.includes('FROM user_roles')) return { rows: [] };
-      if (sql.startsWith('UPDATE schools SET name')) return { rows: [{ id: params[1], name: params[0] }] };
-      if (sql.startsWith('SELECT * FROM classes WHERE id')) return { rows: [{ id: 100, school_id: 2, name: 'Groep 4' }] };
-      if (sql.startsWith('SELECT * FROM users WHERE id') && targetUser) return { rows: [targetUser] };
-      return { rows: [] };
-    },
+    query,
+    // pool.connect() voor transacties (o.a. gebruiker verwijderen)
+    async connect() { return { query, release() {} }; },
   };
   return (async () => {
     const app = Fastify({ trustProxy: 2 });
@@ -194,35 +197,38 @@ test('systeemmanager verplaatst een klas naar een andere school; losmaken kan ni
   await app.close(); await app2.close(); await app3.close();
 });
 
-test('gebruiker verwijderen: FK-fout wordt een nette 409 i.p.v. serverfout', async () => {
-  const calls = [];
-  const pool = {
-    async query(sql, params = []) {
-      calls.push({ sql, params });
-      if (sql.includes('FROM sessions s JOIN users u')) return { rows: [superUser] };
-      if (sql.includes('FROM user_roles')) return { rows: [] };
-      if (sql.startsWith('SELECT * FROM users WHERE id')) return { rows: [{ id: 9, role: 'teacher', school_id: 2, username: 'juf' }] };
-      if (sql.startsWith('DELETE FROM users')) { const e = new Error('fk'); e.code = '23503'; throw e; }
-      return { rows: [] };
-    },
-  };
-  const app = Fastify({ trustProxy: 2 });
-  await app.register(cookie);
-  await app.register(rateLimit, { global: false });
-  app.decorate('pg', pool);
-  await app.register(api, { prefix: '/api' });
-  await app.ready();
+test('gebruiker verwijderen ruimt eerst alle afhankelijke rijen op (geen serverfout)', async () => {
+  const { app, calls } = await makeApp(superUser, { id: 9, role: 'teacher', school_id: 2, username: 'juf' });
   const res = await app.inject({ method: 'DELETE', url: '/api/admin/users/9', cookies });
-  assert.equal(res.statusCode, 409, res.body);
-  assert.match(res.json().error, /gekoppelde gegevens/);
+  assert.equal(res.statusCode, 200, res.body);
+  // in een transactie, afhankelijke tabellen vóór users
+  assert.ok(calls.some((c) => c.sql === 'BEGIN'));
+  assert.ok(calls.some((c) => c.sql.includes('DELETE FROM class_teachers WHERE user_id')));
+  assert.ok(calls.some((c) => c.sql.includes('DELETE FROM assignments WHERE pupil_id')));
+  assert.ok(calls.some((c) => c.sql.includes('DELETE FROM boards WHERE owner_id')));
+  const usersIdx = calls.findIndex((c) => c.sql === 'DELETE FROM users WHERE id = $1');
+  const ctIdx = calls.findIndex((c) => c.sql.includes('DELETE FROM class_teachers'));
+  assert.ok(usersIdx > ctIdx, 'gebruiker wordt pas ná de afhankelijke rijen verwijderd');
+  assert.ok(calls.some((c) => c.sql === 'COMMIT'));
   await app.close();
 });
 
-test('gebruiker verwijderen slaagt normaal (DELETE uitgevoerd)', async () => {
-  const { app, calls } = await makeApp(superUser, { id: 9, role: 'pupil', school_id: 2, username: 'lena' });
+test('als verwijderen tóch faalt, komt de echte reden terug (geen kale serverfout)', async () => {
+  const { app } = await makeApp(superUser, { id: 9, role: 'teacher', school_id: 2, username: 'juf' });
+  const pool = app.pg;
+  const orig = pool.connect.bind(pool);
+  pool.connect = async () => {
+    const client = await orig();
+    const q = client.query;
+    client.query = async (sql, params) => {
+      if (sql === 'DELETE FROM users WHERE id = $1') { const e = new Error('boom'); e.detail = 'Key is still referenced from table "iets".'; throw e; }
+      return q(sql, params);
+    };
+    return client;
+  };
   const res = await app.inject({ method: 'DELETE', url: '/api/admin/users/9', cookies });
-  assert.equal(res.statusCode, 200, res.body);
-  assert.ok(calls.some((c) => c.sql.startsWith('DELETE FROM users')));
+  assert.equal(res.statusCode, 409, res.body);
+  assert.match(res.json().error, /still referenced/);
   await app.close();
 });