diff --git a/dashcaddy-api/__tests__/notification-config-writeback-dc097.test.js b/dashcaddy-api/__tests__/notification-config-writeback-dc097.test.js
new file mode 100644
index 0000000..70ca478
--- /dev/null
+++ b/dashcaddy-api/__tests__/notification-config-writeback-dc097.test.js
@@ -0,0 +1,159 @@
+/**
+ * DC-097: notification-manager `_loadConfig` write-back.
+ * _canonicalizeLegacyKeys (DC-092) fixed legacy spellings in memory only;
+ * the on-disk notifications.json kept `email.user`/`email.pass`, camelCase
+ * event keys, and string `secure` until the next explicit UI save. These
+ * tests pin the new behavior: the canonical form is persisted right after
+ * load, the write is idempotent, and a failed write never blocks startup.
+ */
+
+jest.mock('fs', () => ({
+  existsSync: jest.fn().mockReturnValue(false),
+  readFileSync: jest.fn().mockReturnValue('{}'),
+  writeFileSync: jest.fn(),
+  mkdirSync: jest.fn(),
+}));
+
+jest.mock('nodemailer', () => ({
+  createTransport: jest.fn(() => ({
+    sendMail: jest.fn().mockResolvedValue({ messageId: 'mock' }),
+  })),
+}));
+
+const fs = require('fs');
+const NotificationManager = require('../src/managers/notification-manager');
+
+const NOTIF_FILE = '/tmp/dc097-notif-test.json';
+
+function makeCtx(log) {
+  return {
+    NOTIFICATIONS_FILE: NOTIF_FILE,
+    log,
+  };
+}
+
+// Serializes exactly like the manager does (2-space indent).
+const ser = (obj) => JSON.stringify(obj, null, 2);
+
+function loadWithFile(contents, log) {
+  fs.existsSync.mockReturnValue(true);
+  fs.readFileSync.mockReturnValue(contents);
+  return new NotificationManager(makeCtx(log));
+}
+
+describe('DC-097 notification config canonicalization write-back', () => {
+  let log;
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+    fs.existsSync.mockReturnValue(false);
+    fs.readFileSync.mockReturnValue('{}');
+    fs.writeFileSync.mockClear();
+    log = { error: jest.fn(), info: jest.fn(), warn: jest.fn() };
+  });
+
+  afterEach(() => {
+    try { NotificationManager.prototype.stopHealthDaemon && undefined; } catch (_) {}
+    jest.clearAllMocks();
+  });
+
+  test('legacy file (user/pass, camelCase events, string secure) is rewritten on disk in canonical form', () => {
+    const legacy = {
+      enabled: true,
+      providers: {
+        email: {
+          enabled: true,
+          host: 'smtp.test',
+          port: 465,
+          secure: 'false',
+          to: 'me@test',
+          from: 'from@test',
+          user: 'legacy-user',
+          pass: 'legacy-pass',
+        },
+      },
+      events: {
+        containerDown: false,
+        deploymentSuccess: false,
+      },
+    };
+    const nm = loadWithFile(ser(legacy), log);
+
+    // In-memory: canonical (pinned by DC-092 tests, re-pinned here).
+    expect(nm.config.providers.email.username).toBe('legacy-user');
+    expect(nm.config.providers.email.password).toBe('legacy-pass');
+    expect(nm.config.providers.email.secure).toBe(false);
+    expect(nm.config.events['container-down']).toBe(false);
+    expect(nm.config.events['deploy-success']).toBe(false);
+
+    // On-disk write-back: exactly one write of the full canonical config.
+    expect(fs.writeFileSync).toHaveBeenCalledTimes(1);
+    const [pathArg, contentsArg] = fs.writeFileSync.mock.calls[0];
+    expect(pathArg).toBe(NOTIF_FILE);
+    const written = JSON.parse(contentsArg);
+    expect(written.providers.email.username).toBe('legacy-user');
+    expect(written.providers.email.password).toBe('legacy-pass');
+    expect(written.providers.email.user).toBeUndefined();
+    expect(written.providers.email.pass).toBeUndefined();
+    expect(written.providers.email.secure).toBe(false);
+    expect(written.events['container-down']).toBe(false);
+    written.events && expect(Object.keys(written.events)).not.toContain('containerDown');
+    nm.stopHealthDaemon && nm.stopHealthDaemon();
+  });
+
+  test('write-back is idempotent: an already-canonical file is not rewritten', () => {
+    // First load performs the write-back; capture what it wrote.
+    const legacy = ser({
+      providers: { email: { user: 'u', pass: 'p', secure: 'false' } },
+      events: { containerDown: true },
+    });
+    const first = loadWithFile(legacy, log);
+    expect(fs.writeFileSync).toHaveBeenCalledTimes(1);
+    const canonicalContents = fs.writeFileSync.mock.calls[0][1];
+    first.stopHealthDaemon && first.stopHealthDaemon();
+    fs.writeFileSync.mockClear();
+
+    // Second load against the canonical bytes: no write.
+    const second = loadWithFile(canonicalContents, log);
+    expect(fs.writeFileSync).not.toHaveBeenCalled();
+    expect(second.config.providers.email.username).toBe('u');
+    second.stopHealthDaemon && second.stopHealthDaemon();
+  });
+
+  test('legacy keys absent → no write at all (clean file untouched)', () => {
+    // Fully canonical: matches the merged config after serialization.
+    // Build it by round-tripping: write-back from a minimal legacy file
+    // produces the canonical full shape; feed those exact bytes back.
+    const nm = loadWithFile(ser({ enabled: true }), log); // 1 write (defaults fill-in)
+    const canonicalContents = fs.writeFileSync.mock.calls[0][1];
+    nm.stopHealthDaemon && nm.stopHealthDaemon();
+    fs.writeFileSync.mockClear();
+    const again = loadWithFile(canonicalContents, log);
+    expect(fs.writeFileSync).not.toHaveBeenCalled();
+    again.stopHealthDaemon && again.stopHealthDaemon();
+  });
+
+  test('write failure (EACCES) does not throw out of the constructor and in-memory config stays correct', () => {
+    const legacy = ser({
+      providers: { email: { user: 'u2', pass: 'p2' } },
+      events: { workflowDone: true },
+    });
+    fs.writeFileSync.mockImplementation(() => { throw new Error('EACCES: permission denied'); });
+    let nm;
+    expect(() => { nm = loadWithFile(legacy, log); }).not.toThrow();
+    expect(nm.config.providers.email.username).toBe('u2');
+    expect(nm.config.events['workflow']).toBe(true);
+    // Warn surfaced, no error-level log (load itself succeeded).
+    expect(log.warn).toHaveBeenCalled();
+    expect(log.error).not.toHaveBeenCalled();
+    nm.stopHealthDaemon && nm.stopHealthDaemon();
+  });
+
+  test('no file on disk → no read, no write (fresh install untouched)', () => {
+    fs.existsSync.mockReturnValue(false);
+    const nm = new NotificationManager(makeCtx(log));
+    expect(fs.readFileSync).not.toHaveBeenCalled();
+    expect(fs.writeFileSync).not.toHaveBeenCalled();
+    nm.stopHealthDaemon && nm.stopHealthDaemon();
+  });
+});
diff --git a/dashcaddy-api/src/managers/notification-manager.js b/dashcaddy-api/src/managers/notification-manager.js
index fcb88c0..fef300e 100644
--- a/dashcaddy-api/src/managers/notification-manager.js
+++ b/dashcaddy-api/src/managers/notification-manager.js
@@ -98,15 +98,41 @@ class NotificationManager extends EventEmitter {
   _loadConfig() {
     try {
       if (fs.existsSync(this.NOTIFICATIONS_FILE)) {
-        const data = JSON.parse(fs.readFileSync(this.NOTIFICATIONS_FILE, 'utf8'));
+        const raw = fs.readFileSync(this.NOTIFICATIONS_FILE, 'utf8');
+        const data = JSON.parse(raw);
         this._canonicalizeLegacyKeys(data);
         this.config = this._mergeConfig(DEFAULT_CONFIG, data);
+        this._persistCanonicalForm(raw);
       }
     } catch (error) {
       this.log.error('notification', error, null, { note: 'Failed to load config' });
     }
   }
 
+  /**
+   * DC-097: _canonicalizeLegacyKeys only fixed the file in memory — the
+   * on-disk file kept its legacy spellings (email user/pass, camelCase
+   * event keys, string `secure`) until the next explicit UI save, so any
+   * pre-DC-092 file stayed stale forever on installs that never touch the
+   * settings page. After the defaults merge, persist the canonical form
+   * whenever it differs from what is on disk. Best-effort: the config is
+   * already correct in memory, so a write failure (read-only mount, EACCES)
+   * must never block startup — warn and continue. Idempotent: once written,
+   * the re-serialized form matches the file byte-for-byte and no further
+   * writes happen on subsequent loads.
+   */
+  _persistCanonicalForm(rawFileContents) {
+    try {
+      const canonical = JSON.stringify(this.config, null, 2);
+      if (canonical !== rawFileContents) {
+        fs.writeFileSync(this.NOTIFICATIONS_FILE, canonical);
+        this.log.info?.('notification', 'Notification config canonicalized on disk (legacy keys normalized)', {});
+      }
+    } catch (writeError) {
+      this.log.warn?.('notification', 'Failed to persist canonicalized notification config; continuing with in-memory config', { error: writeError?.message || String(writeError) });
+    }
+  }
+
   /**
    * DC-092: configs saved by older clients may contain the legacy spellings
    * the old POST /config merged verbatim — email.user/email.pass instead of