Microsoft To Do unavailable: how to get it working again

If Microsoft To Do says it’s unavailable, the cause is usually a Microsoft service problem, a sign-in sync issue, or a device-specific app or browser problem. The fastest safe fixes are to check service status, restart the app or browser, and sign out and back in. If it still works on one device, you can usually narrow it down to the other device, browser, or local app data without risking your tasks.

What 'Microsoft To Do unavailable' usually means

What you see can vary, but the meaning is usually the same: To Do can’t reach the service or can’t load your account data.

You might see one of these symptoms:

The exact message varies.

• The app opens and then stays blank or keeps loading.
• Your lists appear missing on one device but not another.
• A browser shows a message that the service is unavailable or the page won’t load.
• You can sign in, but your tasks never sync.
• The app closes right after launch or refuses to refresh.

If your tasks are still visible on another phone, computer, or in the web version, your data is probably still there. That usually points to a sync, sign-in, browser, or local app issue rather than lost tasks.

Before you start

This applies to Microsoft To Do on the web, Windows desktop, iPhone, and Android. The exact steps can vary a little by platform, but the checks below are safe on all of them.

You do not need administrator access for the first checks. Some desktop fixes may need permission to close the app fully or clear browser data, but the safest steps do not require admin rights.

No backup is usually needed before the first round of fixes, because the steps below are meant to avoid deleting your synced tasks. If you plan to remove app data or reinstall later, first confirm your lists still appear on another device or in the web version.

Start with two safe checks:

• Open Microsoft To Do on another device you already use, or try the web version in another browser.
• Check Microsoft’s service status page for Microsoft 365 and related consumer services.

Check whether it’s a Microsoft outage or just your device

Before changing anything on your device, rule out a service-wide problem. If Microsoft’s service is having trouble, local fixes won’t help much until the outage clears.

If To Do fails everywhere at once, the problem is likely on Microsoft’s side. In that case, wait and try again later rather than reinstalling or resetting anything.

If To Do works on one device but not another, the service itself is probably fine. That means you should focus on the problem device, the browser, or the local account cache.

The quickest fixes that solve most cases

Start with the least risky fixes first. These usually solve the problem without affecting your lists.

1. Restart Microsoft To Do completely.

Close the app, then reopen it. On desktop, make sure it’s not just sitting in the taskbar or system tray. On mobile, force-close it from the app switcher and open it again.

If the app loads normally after a restart, the issue was temporary. If it still shows unavailable, move on.

2. Check your internet connection.

Switch between Wi-Fi and mobile data, or open a different website or app that needs the internet. If other services also fail, the problem is not specific to To Do.

If your connection is fine but To Do still will not load, continue.

3. Sign out and sign back in.

This can refresh a stuck token or a broken sync session. Use the same Microsoft account you normally use.

If signing out is difficult because the app won’t finish loading, try the web version instead and sign out there first.

4. Update Microsoft To Do.

Use the app store or your platform’s update tool. A newer version can fix bugs that break sign-in or syncing.

If the app is already current, that does not rule out a local cache problem.

5. Try the web version or another browser.

If the app fails, open To Do in a browser. If the browser version fails, try another browser.

This tells you quickly whether the issue is with the app itself or with the account and service.

On Windows, you can also make sure the app is allowed to run in the background and that date and time are correct. A wrong clock can break sign-in and sync. On iPhone and Android, a full restart of the phone can clear temporary app problems after you’ve tried the simpler steps above.

If only one device is affected

When To Do works on one device but not another, the cause is usually local: cached data, a stuck login, or something on that device blocking the service.

Windows

If the desktop app fails but the web version works, the Windows app likely has stale data. First, sign out inside the app if you can, then close it fully and open it again. If that fails, clear the app’s cache only if you know where your local app data lives, and avoid deleting anything that looks like your actual task store unless you’re certain it is only cache.

If you use the browser version on Windows and only one browser is affected, clear that browser’s cache for Microsoft To Do and disable extensions that filter scripts, privacy requests, or ad content. A strict extension can stop the page from loading correctly even when the service is fine.

iPhone

If To Do works on another device but not your iPhone, force-close the app, reopen it, and check that iOS can reach the internet normally. If the app still says unavailable, sign out and back in if the app allows it. If not, a device restart is a safer next step than reinstalling right away.

Android

On Android, a bad app cache or a background restriction is common. Open the app again after a full close, then check whether battery optimization or data restrictions are limiting it. If the app only fails on mobile data or only on Wi-Fi, the network settings on that device may be the problem.

Web

If the browser version fails but the app works, the browser is usually the issue. Try a private window first. If that works, the problem is almost always cached site data or an extension. Then clear site data for To Do or test with extensions disabled one by one.

Don’t reinstall or wipe app data first if your tasks are not syncing elsewhere yet. If the problem is only a local cache or sign-in issue, a reinstall can make recovery slower and make it harder to tell what was already synced.

If you have to move past the safe fixes, do it in this order: sign out, restart the device, test another browser or profile, and only then reinstall the app if nothing else restores normal loading.

How to clear sync problems without losing tasks

If To Do opens but your lists look wrong, treat it as a sync problem first, not a data-loss problem. The safest way to clear it is to refresh the sign-in session and the local cache before you remove anything.

Start with sign out and sign back in on the device that is misbehaving. That often clears a stuck token without touching your lists.

If the web version works, leave it alone while you fix the problem app or browser. Having one working copy gives you a safe place to confirm that your tasks still exist.

If the issue is only in one browser, clear only the site data for Microsoft To Do instead of clearing all browser data. That keeps your other saved sessions intact and avoids unnecessary logouts from other sites.

If the app still fails after a clean sign-in, restart the device before you reinstall anything. That gives background sync a chance to recover and avoids turning a temporary issue into a harder one.

Avoid reinstalling too early if you have not confirmed your lists still appear elsewhere. Reinstalling is not usually dangerous to your Microsoft account data, but it is a blunt step and can slow down troubleshooting when the real problem is only local.

How to tell the problem is really gone

The fix is working only if To Do behaves normally after a full close and reopen, not just for a few seconds.

You should see all of the following:

• Your lists load without a blank screen or error.
• New edits appear on another device after sync.
• Completed tasks stay completed after reopening the app.
• The same account works in both the app and the web version, if you use both.

A good final check is to add a small test task on one device, wait a moment, then open To Do on another device or in the browser. If the test task appears there and any change you make on the second device also comes back, sync is healthy again.

If the app still opens once but breaks again after a restart, the issue is probably not fully fixed. At that point, recheck sign-in, cached browser data, and any device restrictions that might be blocking the app in the background.

Conclusion

If To Do is still unavailable after these checks, go back to the one device that fails and treat it as a local sync problem, not a lost-data problem. Test the web version, then a different browser or device, and only move to heavier fixes if your lists are safe elsewhere. Once you can add a task and see it appear on another device, you’re done.

Frequently Asked Questions

Will reinstalling Microsoft To Do delete my tasks?

Usually not, because your tasks are tied to your Microsoft account and sync from the service. The safer move is to confirm your lists still appear on another device or in the web version before you uninstall anything.

Why does Microsoft To Do work on my phone but not my PC?

That usually means the PC has a local problem such as cached data, a stuck sign-in, an extension, or a browser issue. If the web version works on the PC, the account is probably fine and the desktop app or browser is the part that needs fixing.

What if Microsoft To Do is unavailable only in my browser?

Try a private window and then another browser. If that works, clear site data for To Do and disable extensions that may block scripts or tracking requests.