Know which installation method you received
| Method | What you should see | What to check |
|---|---|---|
| App Store | An Apple product page and normal Get button | Developer name, reviews and app permissions |
| TestFlight | An invitation that opens in Apple TestFlight | Developer, beta status and expiry information |
| Enterprise distribution | A manually installed app linked to an organisation | The organisation and developer identity before you trust it |
If a page tells an iPhone user to download an APK, it is the wrong file or the instructions are misleading.
Install and verify the iOS app
- Open the link in Safari and check the full destination address.
- Confirm whether it uses the App Store, TestFlight or an enterprise installation.
- Read the developer name before accepting the installation.
- For an enterprise app, check Settings › General › VPN & Device Management only after you have verified the organisation.
- Launch the app and review any request for notifications, photos, location or other device access.
If “Untrusted Enterprise Developer” appears
The warning means iOS has not trusted that manually distributed developer on the device. It is not an instruction to approve every profile. Compare the developer shown in Settings with the identity supplied by a source you already trust. If the names do not match, remove the app.
Why the iOS app may stop opening
- The enterprise certificate was revoked or expired.
- The build no longer supports your iOS version.
- The phone has too little free storage to finish an update.
- A work or school management policy blocks the profile.
- The download was interrupted and left an incomplete app.
A revoked certificate must be resolved by the distributor. Installing more unknown profiles does not fix the underlying problem.
Keep the iPhone account safer
Use a password you do not use for Apple ID, email or banking. Never send a verification code to a person claiming they need it to activate the app. If a support message requests screen sharing or remote control, stop and verify the contact through a known channel.
Related app guides
Using a different phone? Read the MEGA888 Android guide. To compare file types and download checks, open the MEGA888 download guide.
Useful official sources
Last reviewed: 3 September 2026