# Troubleshooting App Installation

Source: https://help.testapp.io/faq/troubleshooting-app-installation/

Installing an app through TestApp.io requires two steps: install the TestApp.io mobile app on your device first, then use it to install the release. Most installation problems fall into a few common categories, use the sections below to find your issue.

## iOS Installation Issues

### 1. Developer Mode not enabled (iOS 16 and later)

iOS 16 and later requires Developer Mode to be enabled before installing apps outside the App Store.

See: [Enable Developer Mode on iOS](https://help.testapp.io/faq/enable-developer-mode-ios/)

### 2. "Untrusted Developer" prompt

After installing the app, you may see "Untrusted Developer" when you try to open it.

- Go to **Settings → General → VPN & Device Management**.
- Find the app's developer certificate and tap **Trust**.
- Open the app again.

### 3. UDID not registered in provisioning profile

If you're trying to install an Ad-Hoc distributed app and it won't install, your device UDID may not be included in the app's provisioning profile.

- Ask the app developer to add your UDID to their Apple Developer account and rebuild.
- To find your UDID: [How to Get Your UDID](https://help.testapp.io/faq/how-to-get-udid/)
- For developers registering UDIDs: [Add UDID to Apple Developer Account](https://help.testapp.io/faq/how-to-add-udid-to-apple-developer-account/)

### 4. Provisioning profile expired

Ad-Hoc and Enterprise certificates expire. If you get an installation error on a previously working build, the provisioning profile may have expired. Contact the app developer to renew and re-distribute.

### 5. Install fails on iPad

Safari on iPad may switch to desktop mode, causing the install page to not trigger the native install prompt.

See: [Installing Apps on iPad with Safari](https://help.testapp.io/faq/enable-mobile-mode-on-safari/)

### 6. Google Advanced Protection program

If you have Google Advanced Protection enabled on your Apple account, app installation may be blocked.

See: [Installing Apps with Google Advanced Protection](https://help.testapp.io/installing-apps-with-google-advanced-protection/)

### 7. Use Safari, not Chrome

iOS requires Safari to trigger the native app install prompt. Chrome and other browsers on iOS cannot install IPA files.

## Android Installation Issues

### 1. "Install unknown apps" or "Unknown sources" blocked

Android blocks installations from outside the Play Store by default. You need to allow installs from the TestApp.io app.

See full steps: [Troubleshooting APK Installation on Android](https://help.testapp.io/faq/troubles-installing-apks-on-android/)

### 2. "Parse error" or "App not installed"

This usually means the APK is incompatible with the device. Common reasons:

- The APK targets a newer Android version than your device runs.
- The APK was built for a different CPU architecture (arm64 only, but your device is armv7).
- The file was corrupted during download. tap the release link again to re-download.

### 3. Google Advanced Protection

See: [Installing Apps with Google Advanced Protection](https://help.testapp.io/installing-apps-with-google-advanced-protection/)

### 4. Previous version already installed

If a previous version of the same app is already installed with a different signing certificate, Android will refuse the install. Uninstall the existing version first, then install the new one.

## Common Issues (iOS and Android)

### The install link not working

- Share links may be password-protected. Check with the person who sent you the link.
- The link may have expired. contact the app developer to send a fresh link.
- Make sure you have the TestApp.io mobile app installed before opening the link.

### App installs but crashes immediately

- The release may have been built with a debug configuration not intended for your device. Contact the developer.
- Try uninstalling and reinstalling via the TestApp.io app.

### Not receiving installation notifications

- Make sure notifications are enabled for the TestApp.io app in your device settings.
- Check that you have been added to the correct app and have the Tester or Guest role.

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## Related Articles

- [Enable Developer Mode on iOS](https://help.testapp.io/faq/enable-developer-mode-ios/)
- [Troubleshooting APK Installation on Android](https://help.testapp.io/faq/troubles-installing-apks-on-android/)
- [How to Get Your UDID](https://help.testapp.io/faq/how-to-get-udid/)
- [Understanding Provisioning Profiles](https://help.testapp.io/understanding-provisioning-profiles-in-app-development/)
- [Installing Apps with Google Advanced Protection](https://help.testapp.io/installing-apps-with-google-advanced-protection/)
- [Getting Started with the Mobile App](https://help.testapp.io/mobile-app-getting-started/)

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