Microsoft To Do official fix for sync and sign-in problems
If Microsoft To Do is out of sync, keeps asking you to sign in, or won’t open, the safest first check is whether the service is down or the problem is only on one device. In most cases, the fix is one of a few official steps: sign out and back in, update the app, clear or reset the app data, and test another network or device. Start with the least invasive step so you do not make a working copy worse.
What’s actually broken: sync, sign-in, or the app itself?
The symptom usually points to the right fix.
If tasks show up on one device but not another, that is usually a sync problem. If the app keeps asking you to sign in again, fails at sign-in, or shows an account error, that is usually an account or authentication problem. If the app opens to a blank screen, freezes, crashes, or never gets past the splash screen, that is usually a local app or device problem.
If the same problem appears across multiple devices and the same account, the issue is more likely on Microsoft’s side or tied to that account. If only one phone or PC is affected, focus on that device first.
A quick way to sort it out:
- If To Do works in the browser but not in the app, the problem is probably the app or device.
- If To Do fails on every device and in the browser, the issue is more likely the account or Microsoft service.
- If To Do works on a different network, the original network is probably the blocker.
Those checks tell you whether to treat it as a service issue, a sign-in issue, or a device issue.
Where this fix applies and where it won’t
These steps fit the common Microsoft To Do problems people run into on the app and in the browser: tasks not updating, repeated sign-in prompts, stale lists, sync delays, blank screens, and app launch failures.
They also apply whether you use To Do on Windows, iPhone, Android, or the web, as long as the issue is tied to your Microsoft account and the app itself.
Before you start, keep these limits in mind:
- You usually do not need administrator rights for the first checks.
- Some Windows repair steps may ask for admin permission if you go as far as app repair or reset.
- A restart is not required for the first checks, and no backup is needed yet.
- If you are worried about changes, do not remove the app first. That is later in the process, not the opening move.
Do two safe checks first:
- Open Microsoft To Do on another device or in a browser.
- Try a different network, such as mobile data instead of Wi‑Fi, or the reverse.
If To Do works elsewhere, the account is probably fine and the problem is local to one device or network. If it fails everywhere, move to the service and account checks first.
The official fixes to try first
Start with the least disruptive fix and move down the list only if the problem stays put.
- Check whether Microsoft To Do is having a service issue.
If the app works on one device but not another, or if many sign-ins fail at once, the problem may be on Microsoft’s side. Check service health for Microsoft 365 or try To Do on the web. If the web version also fails, wait for recovery rather than making bigger changes.
Expected result: the web app opens and shows the same lists, or at least signs you in normally.
If that does not happen on any device, stop chasing local fixes for now. The issue may be with Microsoft’s service or a temporary account problem.
- Sign out of Microsoft To Do and sign back in.
Do this in the app that is failing. Sign out cleanly, close the app, reopen it, and sign back in with the same account.
Expected result: your lists reload and new changes begin syncing again.
If that does not happen, the app may be holding stale sign-in data, so move to the next step.
- Update Microsoft To Do and the device OS.
Use the App Store, Google Play, Microsoft Store, or the built-in updater for your platform. If you are on Windows, also install pending Windows updates.
Expected result: the app should open normally and stop repeating the same error.
If the app still misbehaves after updating, the local app data may be stuck.
- Clear the app cache or reset the app data.
On mobile, clear the app’s cache if the platform offers that option. On Windows, use the app’s repair or reset option in system settings.
Windows Settings > Apps > Installed apps > Microsoft To Do > Advanced optionsExpected result: the app launches with fresh local data and signs you in again.
If the app opens after this but your lists are gone, give it time to resync before assuming data was lost. If it still fails to open, continue.
If you reset app data, some local settings and cached sign-in state can be cleared. Use this step only after sign-out and update have not helped.
- Test another network and another device.
Switch from Wi‑Fi to mobile data, or from mobile data to Wi‑Fi. Then test To Do on a second device or in a browser.
Expected result: if the issue disappears on a different network, the original network may be blocking or delaying Microsoft services. If it only fails on one device, the device is the problem.
If the fix works on one device but not another, keep using the working device as the reference and repair the failing one locally. If only one account fails on a shared device while another account works, that points to the account rather than the device.
If none of these steps changes anything, the issue is usually either account-specific, device-specific, or waiting on a Microsoft-side fix.
How to confirm it’s really fixed
Do not stop at the app opening once. A real fix means sync is healthy, sign-in is stable, and the problem does not return after a restart.
Check these signs:
- Add a small test task on one device.
- Open To Do on a second device or in the web app and confirm the task appears.
- Edit the task, then confirm the change shows up everywhere.
- Close the app completely and reopen it.
Expected result: you stay signed in, the same lists load again, and the test task still matches across devices.
If the app works for a minute and then breaks again, the fix is only partial. That usually points to a cached sign-in problem, a network filter, or a Microsoft service issue that has not fully cleared yet.
If it still doesn’t work
If To Do works on one device but not another, treat the working device as the truth source. That usually means the account is fine and the bad device needs a local repair, not a full account reset.
If you use a work or school account, your organization may have restrictions on sign-in, background sync, or account access. In that case, the issue may sit with account policy rather than the app itself.
If only one account fails while another account works on the same device, the account itself is the likely problem. That can happen with stale tokens, sync state tied to one Microsoft profile, or a Microsoft-side issue affecting a single account.
If every device shows the same failure and the web app also fails, stop making changes and wait a bit before retrying. Repeated resets usually do not help when the backend is down or the account is temporarily stuck.
If the app still fails after sign-out, update, repair or reset, and a different network, contact Microsoft support with the exact symptom, the device type, and the account type you use.
Conclusion
If you want the fastest next step, check To Do on another device or in the web app. If it fails everywhere, wait for Microsoft or contact support; if it works elsewhere, fix the one device that is misbehaving.
Frequently Asked Questions
Why does Microsoft To Do keep asking me to sign in?
That usually means the app is not keeping a valid sign-in token. Sign out, close the app, reopen it, and sign back in. If that still loops, update the app and clear or reset the local app data.
Why do my tasks show up on one device but not another?
That usually points to a sync problem on the device that is out of date. Check whether the app works on the web or on a second device, then sign out and back in on the problem device and try another network. If one device works and another does not, the working device is a better sign that your account is fine.
Should I uninstall Microsoft To Do first?
No. Uninstalling is usually not the first fix. Try sign-out, update, and repair or reset first, because those steps are safer and more likely to preserve your account data.