Close and reopen the app, restart iPhone, update the app and iOS, then delete and redownload the app last. Deletion can remove data stored only inside that app. Settings, Privacy and Security, Analytics shows whether iOS has logged the crash, which helps if you report it to the app's maker.
What this covers
- A downloaded or built-in iPhone app that stops responding or closes
What it does not cover
- ×An iPhone that is frozen at startup or has no usable storage
Try in this order
0 of 4 completedClose and reopen the app
ReversibleOpen the app switcher, swipe the affected app away, then launch it again once.
Restart iPhone
ReversibleUse the normal power-off procedure for the model, wait for shutdown, then turn it on again.
Update the app and iOS
ReversibleInstall the app’s App Store update, then check Settings › General › Software Update.
Delete and redownload last
Signs you outConfirm the app’s data is synced or recoverable and that credentials are available before deleting and reinstalling it.
Evidence ledger
Sources behind this answer
Exact questions
Common questions about “An iPhone app keeps closing, freezing or will not open”
Why does an app keep closing?+
Out-of-date apps, low storage or an iOS bug are common.
Should I reinstall?+
Reinstalling can fix a corrupted app. Check that your data is saved first.
Should I update the iPhone?+
Yes. Updates fix many crashes. Check Settings for iOS and App Store updates.
Would offloading the app help?+
Offloading removes the app but keeps its data, and reinstalling gives you a fresh copy.
Could storage cause crashes?+
Yes. A nearly full iPhone slows apps and causes crashes.
Could a specific iOS version be at fault?+
Occasionally an iOS update introduces a bug that a later update fixes. Check whether other users report the same problem and install any newer version when available.
What if the app crashes right on launch?+
Try deleting and reinstalling it, and check the App Store for an update. If it still crashes on launch, contact the developer and mention your iOS version.
How do I know if it is just one app?+
Try other apps. If only one fails, the fault is with that app or its account. If many apps crash, look at storage, the iOS version or a hardware issue.
Should I contact the developer?+
If the app still crashes after updating and reinstalling, contact the developer with your iPhone model, iOS version and what you were doing when it crashed. That information helps them find the bug.