The “Untrusted Enterprise Developer” alert means iOS hasn’t yet accepted the signing certificate for an app that was installed manually. If the app came from your employer, school, or another organization you recognize, you can establish trust in Settings. On iOS 18 or later, the current process includes an Allow & Restart step; older versions use a Trust button. If the app or developer is unfamiliar, stop and verify it with the organization before proceeding.
Apple’s current instructions for custom enterprise apps cover this manual trust flow. The steps below apply to an enterprise app installed outside the App Store. Managed apps may be trusted automatically by an organization’s device-management system.
When the warning appears, tap Cancel. Confirm the app was distributed through a channel your organization or vendor actually uses, and that the developer name matches what they provided. A trust prompt is not a recommendation to install software: trusting a developer allows its signed apps to open, but it does not tell you whether the app is appropriate for your device or data.
On the iPhone or iPad, open Settings, then go to General > VPN & Device Management. Under Enterprise App, tap the name of the developer associated with the app. The entry may use the organization’s legal name rather than the app’s name.
Review the developer name once more. On iOS 18, iPadOS 18, or later, tap Allow & Restart. Your device restarts; follow any onscreen prompt afterward to finish trusting the developer. On earlier versions, tap Trust and confirm the choice. Then return to the Home Screen and open the app again.
Once a developer is trusted, other manually installed apps signed by that same developer can open without repeating the initial trust step. Only do this for a developer you have independently confirmed.
Certificate verification requires an internet connection. If Settings shows Not Verified, connect to Wi-Fi or cellular data, return to the developer entry, and tap Verify App. If you are on a work or school network, its firewall may need to allow connections to ppq.apple.com, Apple’s verification service. Ask the organization’s IT team to check the network if verification still fails.
Developer Mode is for locally installed development builds, such as apps run from Xcode or installed for testing. It is separate from trusting an enterprise developer; enabling it does not make an unknown app safe. See Apple’s Developer Mode documentation if you are testing your own app.
Likewise, Settings > General > About > Certificate Trust Settings controls full trust for manually installed root certificates used for SSL/TLS connections. It is not the place to approve an enterprise app. Apple explains that separate certificate setting in its certificate-profile guidance.
Only trust an app when you expected to receive it and can confirm the developer through the organization or vendor that supplied it. Do not approve a profile or developer because an unsolicited message tells you to, and don’t treat the button as proof that an app has passed App Store review. If you can’t confirm who signed the app, delete it and obtain software from an official source instead.
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