How to Trust an “Untrusted Developer” App on iPhone

Published by @SoNiceInfo at 6/24/2020 (Updated: 10/20/2026)

When you open an app on your iPhone or iPad, you may see Untrusted Developer and the app won't open. For apps from your company or school, the message may say Untrusted Enterprise Developer.
It appears for apps that didn't come from the App Store, and the app opens once you trust its developer in Settings. The steps below follow the screens in iOS 18 and later.

Why It Appears

Apps installed outside the App Store (in-house apps distributed by a company or school, or apps you built with Xcode) won't open until your iPhone trusts their developer. This is how iOS keeps apps from unknown developers from running on your device.

Only trust a developer when you know where the app came from. If someone you don't know asks you to install an app or a profile, don't trust it.

Trust an App from Your Company or School

1. Close the message with Cancel.
2. Go to Settings > General > VPN & Device Management.
3. Under Enterprise App, tap the developer's name.
4. Tap Trust “(developer name)”.
5. In the confirmation, tap Allow & Restart. After your iPhone restarts, follow the onscreen steps to finish (in iOS 17 and earlier, just tap Trust).

Your iPhone needs an internet connection to verify the developer. If you trust the app while offline, it shows Not Verified; connect to the internet and tap Verify App. Once you trust a developer, other apps from the same developer open right away.

Trust an App You Built with Xcode (for Developers)

Apps you run on a device from Xcode show the same message too, for example when they're signed with a free Apple Account.

1. In iOS 16 and later, turn on Developer Mode first: go to Settings > Privacy & Security > Developer Mode, turn it on, restart, and confirm after the restart. If the option isn't there, connect your iPhone to a Mac with Xcode and it appears.
2. After installing the app, go to Settings > General > VPN & Device Management.
3. Under Developer App, tap Apple Development: (your Apple Account email).
4. Tap Trust “Apple Development: …” and allow it in the confirmation.

These screens are from iOS 13. In current iOS, Profiles & Device Management is called VPN & Device Management. Older guides that say Settings > General > Profiles mean the same screen.
Apps signed with a free Apple Account expire after 7 days and stop opening; install them again from Xcode.

If the App Still Won't Open

If the developer's certificate has been revoked or has expired, the app won't open even after you trust it. For a company or school app, ask whoever distributed it for a new version. Your iPhone also re-verifies trusted developers from time to time, so if it has been offline for a while, it may warn you that the trust is about to expire.