If Office 365 is freezing on your iPhone, the app is usually stuck on a bad sign-in token, a corrupted cache, or a background sync issue. You should be able to fix it by forcing the app closed, updating it, and signing back in cleanly. This guide walks you through the fastest fixes for Office 365 on iPhone and shows you when the problem points to something deeper.
Quick fix
The single most likely fix is to force close Office 365, restart your iPhone, then update the app from the App Store and sign in again. That clears the stuck session that most often causes the freeze. If Office 365 opens normally after that, the problem was a bad app state, not your account or your iPhone.
Why this happens
Office 365 freezes on iPhone when the app gets stuck trying to load mail, files, or account data from Microsoft’s servers. A damaged cache, a half-finished update, or a stale sign-in token can lock the app on the loading screen or make it stop responding after a few taps. Low storage and iOS background restrictions add extra pressure, especially if Outlook, Word, or OneDrive are all trying to sync at once.
How to fix it
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Force close Office 365 completely.
Swipe up from the bottom of the screen and pause, then swipe the Office 365 app card off the top of the screen. On an iPhone with a Home button, double-click the Home button and swipe the app away. Reopen the app only after it disappears from the app switcher. -
Restart your iPhone.
Hold the side button and either volume button, then slide to power off. Wait 20 seconds, then turn the iPhone back on. A restart clears temporary memory that can keep Office 365 frozen even after you close it. -
Update Office 365 from the App Store.
Open the App Store, tap your profile icon, and pull down to refresh the updates list. Install any Office 365, Outlook, Word, Excel, or OneDrive update that appears there. If the app freezes because a component is out of sync, updating it resolves the crash loop and lets it launch normally. -
Sign out and sign back in.
Open Office 365, tap your profile picture or initials, then choose Settings and Sign Out. Close the app again, reopen it, and sign in with the same Microsoft account. This forces the app to rebuild its authentication data, which fixes freezes caused by a broken login session. -
Clear the app by deleting and reinstalling it.
Press and hold the Office 365 app icon, tap Remove App, then tap Delete App. Go back to the App Store, search for Office 365, and install it again. Reinstalling removes corrupted local files and resets the app’s cached data without changing your Microsoft account. -
Check iPhone storage and iOS background limits.
Open Settings > General > iPhone Storage and make sure you have several gigabytes free. Then go to Settings > General > Background App Refresh and confirm it is turned on for Office 365. When storage is nearly full, Office 365 can hang while loading attachments, files, or sync data, and background refresh keeps the app from stalling during login and sync.
Common error messages
“Office 365 is no longer responding.” This means the app has locked up hard and iOS is waiting for it to recover, which almost always points to a frozen session or corrupted local data.
“Something went wrong, please try again.” This is a sign that Office 365 cannot finish loading account or sync data and needs a fresh sign-in or reinstall.
“Cannot connect to server.” This means the app is stuck before it can reach Microsoft’s services, either because the saved session is bad or the network request is failing inside the app.
“If you keep getting signed out, tap to retry.” This points to an authentication loop, where Office 365 cannot hold onto your login token long enough to finish loading.
When this means it’s a bigger problem
If Office 365 still freezes after a reinstall, after you sign in with a different Microsoft account, and after the same behavior appears on a second iPhone, the issue is no longer local to your device. At that point the problem is tied to the account, the service connection, or a deeper app compatibility fault, and you should contact Microsoft support or your organization’s help desk with the exact app screen and error text.
Helpful answers
Frequently Asked Questions
How long does it take for Office 365 to stop freezing after I fix it on iPhone?
The change takes effect as soon as you relaunch Office 365 after force closing it, restarting your iPhone, or signing back in. If the freeze is caused by a bad session or cache, you see the difference immediately. If it still hangs after a reinstall, the issue is deeper than the local app state.
Will deleting and reinstalling Office 365 remove my Microsoft account data?
No. Deleting Office 365 removes the app and its local cached files from your iPhone, but it does not erase your Microsoft account, mailbox, or cloud files. When you reinstall and sign in again, your data syncs back from Microsoft’s servers. Any offline drafts stored only in the app need separate recovery.
What if Office 365 still freezes after I reinstall it?
If a clean reinstall does not fix the freeze, the problem is no longer a corrupted local install. Try signing in on another Microsoft account, then test the same account on a second iPhone. If both devices freeze, the issue is tied to the account, service connection, or a deeper compatibility fault. Check related account sign-in problems
Do I need Background App Refresh turned on for Office 365 to work normally?
Yes, if you want Office 365 to stay responsive during sync and login. Background App Refresh keeps the app from stalling when it loads mail, files, and account data. If it is off, Office 365 can hang on startup or during syncing, especially after you have just reinstalled or signed back in.
Can I undo these fixes and go back to the old Office 365 state on iPhone?
You can reverse most changes by signing back in and reinstalling the app, but you cannot restore a deleted app’s local cache. If you remove Office 365 and set it up again, it starts with fresh data. To go back from a deeper cleanup, use a full account re-sync rather than trying to recover the old app state.