How to Trust a Profile on iPhone (Fix "Untrusted Developer")

After installing an app outside the App Store, the first launch may say "Untrusted Enterprise Developer" and refuse to open. That's normal — you just need to trust the profile once. Here are the exact steps.

Why trust a profile?

Apps installed via signing (not the App Store) aren't trusted by iOS by default, for safety. Trusting it once lets it run and doesn't harm your phone's security.

Trust the profile: step by step

1. Open Settings → General.
2. Scroll to VPN & Device Management (older iOS: "Profiles & Device Management").
3. Under "Enterprise App", tap the developer of the app you just installed.
4. Tap Trust, then confirm.

Back on the home screen, the app now opens normally.

Can't see "VPN & Device Management"?

It only appears after you install a profile that needs trusting. If it's missing, the app probably isn't installed yet, or you already trusted it.