Tasks sync failure - Outlook web vs mobile Outlook vs desktop Outlook

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### **Issue resolved!**

It was caused by **web‑app‑only corruption** in cached scripts and local databases, amplified by uBlock Origin blocking Microsoft telemetry. Clearing all local storage and allowing telemetry restored full sync functionality.

Specifically:

- uBlock Origin blocked critical Microsoft telemetry endpoints

- Cached service worker + cached scripts caused TrustedScriptURL and CORS failures

- IndexedDB corruption prevented full task hydration

- Sync engine could start but not finish, leaving OWA stuck in “Synchronization in progress”

### **Fix Implemented**

1. Whitelisted Microsoft sync + telemetry domains in uBlock Origin

2. Disabled uBlock for outlook.live.com

3. Unregistered Outlook Web App service worker

4. Cleared **all** Outlook Web App site storage:

- Cookies

- LocalStorage

- SessionStorage

- IndexedDB

- CacheStorage

5. Performed a hard reload (`Ctrl + Shift + R`)

6. Reopened the Tasks page to trigger a full sync + hydration rebuild

### **Outcome**

- Sync engine now starts and completes successfully

- Hydration fully rebuilt

- All task lists populated correctly

- Desktop ↔ Mobile ↔ Web sync is immediate and reliable

- Creating, editing, and deleting tasks syncs across all platforms as expected

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