sync
6 TopicsTasks sync failure - Outlook web vs mobile Outlook vs desktop Outlook
--- # 📄 **Technical Report: Persistent Outlook Web App Sync Failure Affecting Microsoft To Do / Outlook Tasks Ecosystem** **Issue Duration:** At least 3 months probably more **Platforms Affected:** - Microsoft To Do (Android) - Outlook Tasks (Windows Desktop Outlook) - Outlook Tasks (Outlook Web App) - Exchange Online (backend sync service) --- ## 1. **Executive Summary** I have experience **persistent, intermittent, and platform‑specific synchronization failures** within the Microsoft To Do / Outlook Tasks ecosystem. The critical finding is: ### **The Outlook Web App is often isolated and does not sync with any other platform.** Meanwhile: - **Windows Desktop Outlook ↔ Android To Do sync perfectly in both directions.** - **Outlook Web App ↔ (Desktop / Android)** do not sync. This isolates the issue to the **web app’s sync pipeline**, not the task data, not the account, and not the other apps. The failures present as: - **“Synchronization in progress”** stuck indefinitely - **“Synchronization failed”** when manually attempting sync - Web app showing **stale, outdated, or incomplete task lists** - Web app failing to send or receive updates from Exchange Online The same tasks that fail to sync for hours later sync successfully without any modification, proving the data is not corrupted and the failure is backend‑related. --- ## 1.1 **Cross‑Platform Sync Behavior (Critical Diagnostic Insight)** ### ✔ **Windows Desktop Outlook ↔ Android To Do** - Full two‑way sync - Immediate updates - Reliable and consistent ### ✖ **Outlook Web App ↔ Desktop Outlook** - No sync in either direction ### ✖ **Outlook Web App ↔ Android To Do** - No sync in either direction ### ✖ **Outlook Web App ↔ Exchange Online** - Appears to be failing or stalling This proves the web app is **not participating in the sync ecosystem**. --- ## 2. **Symptoms Observed** ### 2.1 **Outlook Web App** - Sync button stuck on **“Synchronization in progress”** for hours - Manual sync results in **“Synchronization failed”** - Web app shows outdated task lists - Web app does not receive updates from desktop or mobile - Web app does not send updates to desktop or mobile ### 2.2 **Android To Do** - Tasks created on Android do not appear in the web app - Tasks created in the web app do not appear on Android - Edits fail to propagate to the web app - Manual sync does not resolve the issue - Logout/login sometimes helps, inconsistently ### 2.3 **Windows Desktop Outlook** - Syncs perfectly with Android - Does not sync with the web app - Shows correct, up‑to‑date task data ### 2.4 **Platform Sync Matrix** | Action | Desktop Outlook | Android To Do | Outlook Web App | |--------|-----------------|---------------|------------------| | Create/edit task on **Desktop** | ✔ Syncs to Android | ✔ | ✖ No sync to Web | | Create/edit task on **Android** | ✔ Syncs to Desktop | ✔ | ✖ No sync to Web | | Create/edit task on **Web** | ✖ No sync to Desktop | ✖ | ✔ Stays only on Web | **Conclusion:** The Outlook Web App is **fully isolated** from Exchange Online’s task sync pipeline. --- ## 3. **Troubleshooting Steps Already Attempted** ### 3.1 **Web App** - Hard refresh (Ctrl + Shift + R) - Full browser cache clear - Logout → close browser → reopen → login - Switching lists to force metadata reload - Creating tasks to trigger sync events - Deleting tasks to force backend updates ### 3.2 **Android** - Manual sync - Clear cache - Logout/login - Device restart - Network switching - Creating/completing tasks to trigger sync ### 3.3 **Desktop Outlook** - Verified account health - Verified Exchange Online connectivity - Verified task folder integrity ### 3.4 **Account / Backend** - Verified Microsoft Account stability - Verified no multi‑account conflicts - Verified Exchange Online service health None of these steps produce consistent or lasting resolution. --- ## 4. **Frequency and Pattern** - Occurs multiple times per week - Occurs regardless of recent task edits - Occurs across multiple browsers - Occurs across multiple Android versions - Sync resumes randomly after hours - Sync resumes without any data changes - Sync resumes after logout/login, but inconsistently This pattern strongly suggests **backend sync token stalling**. --- ## 5. **Technical Analysis** ### 5.1 **Two‑Way Sync Failure Confined to Web App** Because: - Desktop ↔ Android works - Web ↔ (Desktop / Android) fails The failure is isolated to the **web app’s connection to Exchange Online**. ### 5.2 **Sync Token Stalling (Most Likely Cause)** Symptoms match known sync token stall behavior: - Endless “Synchronization in progress” - Manual sync fails - Sync resumes randomly - Sync resumes after forced metadata refresh - Sync resumes after unrelated actions (e.g., completing a task) ### 5.3 **Not a Corrupted Task Issue** Because the same tasks later sync successfully: - No malformed tasks - No unsupported metadata - No blocked sync queue - No corrupted lists ### 5.4 **Backend Sync Pipeline Instability** The pipeline: **Web App → Microsoft Sync Service → Exchange Online → Desktop / Android** appears to be failing at the **first hop** (web app → sync service). ### 5.5 **Web App Lacks Retry Logic** The web app provides: - No manual retry - No way to cancel a stuck sync - No way to reset sync session - No way to regenerate sync token Thus, when the backend stalls, the web app remains stuck indefinitely. ### 5.6 **Android Background Sync Not the Cause** Android is syncing perfectly with desktop Outlook, proving Android is not the source of the issue. ### 5.7 **Web App Sync Isolation (New Insight)** The web app is the **only** platform failing to communicate with Exchange Online. This is now clearly a **web‑app‑specific sync session failure**, not a multi‑platform issue. --- ## 6. **Impact** - Tasks frequently out of sync - Web app becomes unusable for task management - Daily workflow disrupted - Manual intervention required multiple times per week - Task state inconsistent across platforms - Reduced confidence in Microsoft To Do as a reliable ecosystem --- ## 7. **Requested Assistance** ### 7.1 **Engineering‑Level Investigation** Specifically into: - Outlook Web App sync token behavior - Web app → Exchange Online sync session stability - Backend retry logic - Web app sync error handling - Web app task API connectivity ### 7.2 **Diagnostic Tools** If available: - Sync session logs - Sync token status - Task metadata inspection tools - Backend queue visibility - Error codes beyond “Synchronization failed” ### 7.3 **Known Issues** Requesting documentation on: - Known To Do / Outlook Web sync token stalls - Known Exchange Online sync delays - Known intermittent sync failures - Known web app pipeline instability ### 7.4 **Confirmation Whether This Is a Known Issue** Given the duration and reproducibility, this appears to be a **backend‑level web app sync failure**. ### 7.5 **Request for Web App Sync Session Reset** Specifically: - Manual reset of the web app’s sync session - Forced regeneration of sync token - Flush of stuck sync queues - Verification of web app’s Exchange Online connectivity --- ## 8. **Evidence Available** I can provide: - Screenshots of “Synchronization failed” - Screenshots of “Synchronization in progress” - Timeline of sync failures - Android device logs - Browser console logs --- ## 9. **Conclusion** This is a **persistent, platform‑specific sync failure** affecting only the Outlook Web App. Desktop Outlook and Android To Do sync perfectly, proving the backend and data are healthy. The web app is isolated and failing to communicate with Exchange Online. I am requesting **engineering‑level support** to reset or repair the web app’s sync session and investigate the underlying cause. ---Solved78Views0likes1CommentSynchronization issue
I have an active Microsoft 365 subscription. My wife and I share Microsoft To Do lists. We recently noticed a synchronization issue: When she creates/deletes/updates tasks, they sync to me. When I create/update tasks, they don’t sync to her. When I delete tasks, they are deleted for her. We’ve already signed out and back in, and tested on different devices and platforms. Permissions are correct, and everything used to work before.1KViews4likes8CommentsMicrosoft To-Do Unable to sync (Win, Android, Web application)
Hi, very strange problem with To-Do what makes it useless. I've got "Unable to sync" information on Windows app, Android app and, what is really strange, also in web application (it's under right-top question mark icon). I used it since few months and it works great. Few days ago stopped. Removed all data on all systems, logout everywhere and delete apps. It changes nothing. After fresh installations problem still exists. Even on different devices. Deleted also all tasks in old Outlook tasks, changed password... nothing helps. When I added second account in To-Do Windows app it works ok. Mine account isn't. Technical support after few email didn't give me any advice how to solve it - just some links how can I restore lost tasks (it's not problem - I want sync back again). I think web application (https://to-do.microsoft.com) sync problem is something what can be first element to think about. Can you please help me? Any way to reset/restore to-do account?2.8KViews0likes1CommentTo-do Outlook meeting sync
so I have started to use Microsoft todo as our workplace uses all Microsoft suite of tools So I’m trying to setup Microsoft todo in a way I use my personal management system we’re all events are inside my task manager I want to be able to show meeting arranged in outlook/teams in Microsoft to do. I know you can share todos into outlook calendar But I want it to be the other way and show meetings in todo So my todo is a list of my entire day not just tasks. Moving tasks into the calendar is just cumbersome both on outlook and outlook web specially on Mac. Just want to be able to auto sync meetings into todo as I don’t always have outlook or teams open Is this possible Like this1.6KViews1like1CommentShared list between personal and business - sync not working
Hello everyone I recently asked myself if it is possible to share a ToDo list between a personal and business account. Well, I found on this https://support.microsoft.com/en-us/office/create-and-share-lists-4e5aeac6-8649-4813-aae5-2c2ddea2f292 that it is possible but only when the personal account is the owner of the list and shares it with a business account. So, I tried it by myself and I got it to work but not as good as I hoped. I can join the list with my business account but when I add a task it won't sync it and doesn't show up in the list on the personal account. Bizarrely when I add a task from the personal account side it syncs the task, and It will be shown on my side with the business account. I tried it with personal to personal account as well and this one works perfectly... Thanks for your responses.1.7KViews0likes0Comments