App crashing

Question

My daughters authentication app on her iphone immediately crashes and closes when she opens it. We’ve deleted and reinstalled. There’s no new update. She needs to use it to get into college email. What do we do?

Answer 1

Dear @Joe Hayes,

I understand how frustrating it is when the Microsoft Authenticator app crashes, especially when it is blocking access to important college emails. Since deleting and reinstalling the app didn't resolve the issue, the problem is likely tied to corrupted local cache data, an outdated iOS version, or an account conflict stored in the device's iCloud keychain.

Please try the following troubleshooting steps in order to get the app stabilized immediately:

Step 1: Clear the App Cache via iPhone Settings

Sometimes a standard deletion leaves behind corrupted data.

• Go to your iPhone Settings > General > iPhone Storage.
• Scroll down and select Authenticator.
• Tap Offload App (this frees up storage used by the app but keeps its documents and data).
• Afterward, tap Reinstall App from the same screen.

Step 2: Check for iOS System Updates

The Authenticator app frequently updates its security protocols, which can cause stability issues if the iPhone's operating system is outdated.

• Go to Settings > General > Software Update.
• If an update is available, please install it and try opening the app again.

Step 3: Disconnect and Re-Register the Device

If the app still crashes, the device registration token on the college's end might be broken. You will need to re-register the app:

• Log into Account Settings: Have your daughter go to mysignins.microsoft.com on a computer or alternative device.
• Remove the Old App Instance: Under Security info, find the Microsoft Authenticator registration for her iPhone and click Delete.
• Re-add the Account: Open the newly reinstalled app on the iPhone, select Add Account > Work or school account, and scan the QR code provided on the computer screen to set it up fresh.

If she cannot log into the Mysignins page because she is completely locked out by Multi-Factor Authentication (MFA), she will need to contact her college's central IT helpdesk. A tenant administrator must temporarily clear her MFA session or change her authentication method so she can log in and re-register her phone.

Please let me know if any of these step's work or if you need further assistance!

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Answer 2

Try these steps to resolve Microsoft Authenticator crashing on iOS:

1. Fully remove and reinstall the app
   Since deletion and reinstall were already tried once, repeat but ensure it is a clean reinstall:
   • Delete Microsoft Authenticator from the iPhone.
   • Restart the iPhone.
   • Install the latest version again from the App Store using the same Apple ID.
2. Check for “Authentication did not complete” conditions
   Even if the app crashes, verify these common causes once the app opens successfully:
   • Make sure the device has a stable internet connection (try switching between Wi‑Fi and mobile data).
   • Confirm the iPhone’s date and time are set correctly (Settings → General → Date & Time → Set Automatically).
   • Ensure notifications are enabled for Microsoft Authenticator (Settings → Notifications → Authenticator).
3. If the app remains unusable, remove and re-add Authenticator as a sign‑in method
   From the college account’s security page (usually via a browser on a computer):
   • Sign in to the Microsoft account used for the college email.
   • Go to the security info section.
   • Remove Microsoft Authenticator as a sign‑in method.
   • Add Microsoft Authenticator again and follow the setup flow with the reinstalled app on the iPhone.
4. If sign‑in is still blocked
   If the app continues to crash or cannot be set up, contact the college’s IT or Microsoft 365 admin and ask them to reset MFA or remove the current Authenticator registration so it can be reconfigured.

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References:

• Troubleshoot problems with Microsoft Authenticator
• Authentication did not complete
• Authenticator locked and cannot access at all after replacing phone - Microsoft Q&A
• Cannot unlock the Autheticator - Microsoft Q&A