diff --git a/docs/styling-guide.md b/docs/styling-guide.md
index fa4972b1ae..4586bd0c55 100644
--- a/docs/styling-guide.md
+++ b/docs/styling-guide.md
@@ -120,17 +120,18 @@ Quickest adoption — add the `.focus-ring` utility class from `util.scss`, whic
 
 ## Z-Index Layers
 
-| Variable                | Value | Purpose                  |
-| ----------------------- | ----- | ------------------------ |
-| `--z-check-done`        | 11    | Task done checkbox       |
-| `--z-main-header`       | 12    | Main header              |
-| `--z-task-title-focus`  | 32    | Focused task title       |
-| `--z-mobile-bottom-nav` | 50    | Mobile bottom navigation |
-| `--z-side-nav`          | 60    | Side navigation          |
-| `--z-backdrop`          | 222   | Backdrop overlay         |
-| `--z-add-task-bar`      | 999   | Add task bar             |
-| `--z-search-bar`        | 999   | Search bar               |
-| `--z-tour`              | 1001  | Tour overlay             |
+| Variable                 | Value | Purpose                  |
+| ------------------------ | ----- | ------------------------ |
+| `--z-check-done`         | 11    | Task done checkbox       |
+| `--z-main-header`        | 12    | Main header              |
+| `--z-task-title-focus`   | 32    | Focused task title       |
+| `--z-mobile-bottom-nav`  | 50    | Mobile bottom navigation |
+| `--z-side-nav`           | 60    | Side navigation          |
+| `--z-backdrop`           | 222   | Backdrop overlay         |
+| `--z-add-task-bar`       | 999   | Add task bar             |
+| `--z-search-bar`         | 999   | Search bar               |
+| `--z-onboarding-presets` | 999   | Onboarding preset screen |
+| `--z-tour`               | 1001  | Tour overlay             |
 
 ## Layout Variables
 
diff --git a/src/app/features/onboarding/onboarding-preset-selection.component.html b/src/app/features/onboarding/onboarding-preset-selection.component.html
index b2c76775ef..af31617427 100644
--- a/src/app/features/onboarding/onboarding-preset-selection.component.html
+++ b/src/app/features/onboarding/onboarding-preset-selection.component.html
@@ -33,7 +33,7 @@
       <button
         type="button"
         class="sync-cta-link"
-        [disabled]="!!selectedPreset()"
+        [disabled]="!!selectedPreset() || isSyncSetupInProgress()"
         (click)="setupSync()"
       >
         {{ 'ONBOARDING.SYNC_CTA_LINK' | translate }}
diff --git a/src/app/features/onboarding/onboarding-preset-selection.component.scss b/src/app/features/onboarding/onboarding-preset-selection.component.scss
index ea38dccd2e..cbd16c8cbe 100644
--- a/src/app/features/onboarding/onboarding-preset-selection.component.scss
+++ b/src/app/features/onboarding/onboarding-preset-selection.component.scss
@@ -4,7 +4,7 @@
   // 999, not 1000: stay just below the CDK overlay container (z-index 1000) so
   // dialogs opened from here (e.g. the sync setup dialog) render above this
   // opaque backdrop rather than relying on a same-z-index DOM-order tiebreak
-  z-index: 999;
+  z-index: var(--z-onboarding-presets);
 }
 
 .onboarding-backdrop {
diff --git a/src/app/features/onboarding/onboarding-preset-selection.component.spec.ts b/src/app/features/onboarding/onboarding-preset-selection.component.spec.ts
index 3968abfb9a..191ab9e7da 100644
--- a/src/app/features/onboarding/onboarding-preset-selection.component.spec.ts
+++ b/src/app/features/onboarding/onboarding-preset-selection.component.spec.ts
@@ -5,7 +5,7 @@ import {
   signal,
   WritableSignal,
 } from '@angular/core';
-import { of } from 'rxjs';
+import { Subject } from 'rxjs';
 
 import { OnboardingPresetSelectionComponent } from './onboarding-preset-selection.component';
 import { ONBOARDING_PRESETS } from './onboarding-presets.const';
@@ -17,13 +17,15 @@ describe('OnboardingPresetSelectionComponent', () => {
   let component: OnboardingPresetSelectionComponent;
   let mockDialog: jasmine.SpyObj<MatDialog>;
   let cfgSignal: WritableSignal<{ sync: { isEnabled: boolean } }>;
+  let afterClosed$: Subject<void>;
 
   const setup = (): void => {
     cfgSignal = signal({ sync: { isEnabled: false } });
+    afterClosed$ = new Subject<void>();
 
     mockDialog = jasmine.createSpyObj('MatDialog', ['open']);
     mockDialog.open.and.returnValue({
-      afterClosed: () => of(undefined),
+      afterClosed: () => afterClosed$.asObservable(),
     } as unknown as MatDialogRef<unknown>);
 
     const mockGlobalConfig = jasmine.createSpyObj('GlobalConfigService', [], {
@@ -44,11 +46,13 @@ describe('OnboardingPresetSelectionComponent', () => {
 
   beforeEach(() => {
     localStorage.removeItem(LS.ONBOARDING_PRESET_DONE);
+    localStorage.removeItem(LS.ONBOARDING_HINTS_DONE);
     setup();
   });
 
   afterEach(() => {
     localStorage.removeItem(LS.ONBOARDING_PRESET_DONE);
+    localStorage.removeItem(LS.ONBOARDING_HINTS_DONE);
   });
 
   describe('setupSync', () => {
@@ -64,25 +68,55 @@ describe('OnboardingPresetSelectionComponent', () => {
     });
 
     it('dismisses onboarding when sync was enabled in the dialog', async () => {
-      cfgSignal.set({ sync: { isEnabled: true } });
       let dismissedCount = 0;
       component.dismissed.subscribe(() => dismissedCount++);
 
       await component.setupSync();
+      expect(dismissedCount).toBe(0);
+      expect(localStorage.getItem(LS.ONBOARDING_PRESET_DONE)).toBeNull();
+
+      cfgSignal.set({ sync: { isEnabled: true } });
+      afterClosed$.next();
 
       expect(dismissedCount).toBe(1);
       expect(localStorage.getItem(LS.ONBOARDING_PRESET_DONE)).toBe('true');
+      expect(localStorage.getItem(LS.ONBOARDING_HINTS_DONE)).toBe('true');
     });
 
     it('keeps onboarding open when sync was not enabled (dialog cancelled)', async () => {
-      cfgSignal.set({ sync: { isEnabled: false } });
       let dismissedCount = 0;
       component.dismissed.subscribe(() => dismissedCount++);
 
       await component.setupSync();
+      afterClosed$.next();
 
       expect(dismissedCount).toBe(0);
       expect(localStorage.getItem(LS.ONBOARDING_PRESET_DONE)).toBeNull();
+      expect(localStorage.getItem(LS.ONBOARDING_HINTS_DONE)).toBeNull();
+    });
+
+    it('does not open duplicate dialogs while sync setup is already active', async () => {
+      const firstSetup = component.setupSync();
+      const secondSetup = component.setupSync();
+
+      await Promise.all([firstSetup, secondSetup]);
+
+      expect(mockDialog.open).toHaveBeenCalledTimes(1);
+
+      afterClosed$.next();
+      await component.setupSync();
+
+      expect(mockDialog.open).toHaveBeenCalledTimes(2);
+    });
+
+    it('does not open a stale dialog if a preset is selected while sync setup is loading', async () => {
+      const setupPromise = component.setupSync();
+      component.selectedPreset.set(ONBOARDING_PRESETS[0]);
+
+      await setupPromise;
+
+      expect(mockDialog.open).not.toHaveBeenCalled();
+      expect(component.isSyncSetupInProgress()).toBeFalse();
     });
   });
 });
diff --git a/src/app/features/onboarding/onboarding-preset-selection.component.ts b/src/app/features/onboarding/onboarding-preset-selection.component.ts
index 694ceda84b..cbab1a3d4a 100644
--- a/src/app/features/onboarding/onboarding-preset-selection.component.ts
+++ b/src/app/features/onboarding/onboarding-preset-selection.component.ts
@@ -12,6 +12,9 @@ import { ONBOARDING_PRESETS, OnboardingPreset } from './onboarding-presets.const
 import { GlobalConfigService } from '../config/global-config.service';
 import { LS } from '../../core/persistence/storage-keys.const';
 
+type DialogSyncCfgComponentType =
+  typeof import('../../imex/sync/dialog-sync-cfg/dialog-sync-cfg.component').DialogSyncCfgComponent;
+
 @Component({
   selector: 'onboarding-preset-selection',
   changeDetection: ChangeDetectionStrategy.OnPush,
@@ -26,6 +29,7 @@ export class OnboardingPresetSelectionComponent {
   presetSelected = output<void>();
   dismissed = output<void>();
   selectedPreset = signal<OnboardingPreset | null>(null);
+  isSyncSetupInProgress = signal(false);
 
   selectPreset(preset: OnboardingPreset): void {
     if (this.selectedPreset()) {
@@ -38,19 +42,35 @@ export class OnboardingPresetSelectionComponent {
   }
 
   async setupSync(): Promise<void> {
-    if (this.selectedPreset()) {
+    if (this.selectedPreset() || this.isSyncSetupInProgress()) {
       return;
     }
-    const { DialogSyncCfgComponent } =
-      await import('../../imex/sync/dialog-sync-cfg/dialog-sync-cfg.component');
+    this.isSyncSetupInProgress.set(true);
+
+    let DialogSyncCfgComponent: DialogSyncCfgComponentType;
+    try {
+      ({ DialogSyncCfgComponent } =
+        await import('../../imex/sync/dialog-sync-cfg/dialog-sync-cfg.component'));
+    } catch (e) {
+      this.isSyncSetupInProgress.set(false);
+      throw e;
+    }
+
+    if (this.selectedPreset()) {
+      this.isSyncSetupInProgress.set(false);
+      return;
+    }
+
     const dialogRef = this._matDialog.open(DialogSyncCfgComponent);
     dialogRef.afterClosed().subscribe(() => {
+      this.isSyncSetupInProgress.set(false);
       // A returning user who actually enabled sync (e.g. to restore data from
       // another device) should not be forced to pick a preset afterwards —
       // that would overwrite the appFeatures config they just synced down.
       // Dismiss onboarding instead, without starting the new-user hint tour.
       if (this._globalConfigService.cfg()?.sync.isEnabled) {
         localStorage.setItem(LS.ONBOARDING_PRESET_DONE, 'true');
+        localStorage.setItem(LS.ONBOARDING_HINTS_DONE, 'true');
         this.dismissed.emit();
       }
     });
diff --git a/src/assets/i18n/en.json b/src/assets/i18n/en.json
index b35e24c8d6..ac682fc3e0 100644
--- a/src/assets/i18n/en.json
+++ b/src/assets/i18n/en.json
@@ -2638,7 +2638,7 @@
   "ONBOARDING": {
     "TITLE": "How do you want to use Super Productivity?",
     "SUBTITLE": "Pick a setup that matches your workflow. You can always change this later in Settings.",
-    "PRIVACY_HINT": "Your data stays securely on your device. Nothing is sent to a server.",
+    "PRIVACY_HINT": "Your data stays securely on your device unless you choose to set up sync.",
     "SYNC_CTA": "Already using Super Productivity on another device?",
     "SYNC_CTA_LINK": "Set up sync",
     "PRESETS": {
diff --git a/src/styles/_css-variables.scss b/src/styles/_css-variables.scss
index 4bfa436021..5b4208ed14 100644
--- a/src/styles/_css-variables.scss
+++ b/src/styles/_css-variables.scss
@@ -161,6 +161,7 @@
   // NOTE needs to be below the z-index of cdk-overlay which is 1000
   --z-add-task-bar: 999;
   --z-search-bar: 999;
+  --z-onboarding-presets: 999;
   --z-mobile-bottom-nav: 50;
   --z-right-panel: 44;
   --z-right-panel-resize-handle: 65;