How to Trust Enterprise Developer Certificates on iPhone

ByScarlet iOS Team Updated on

What Is an Enterprise Developer Certificate?

An enterprise developer certificate is a credential issued by Apple to qualifying organizations through its Apple Developer Enterprise Program. It allows those organizations to distribute internal iOS apps to their employees without going through the public App Store. Unlike standard individual developer certificates, enterprise certificates are not restricted to a specific list of device UDIDs: they can authorize installation on any device that trusts the certificate.

Third-party app installers like Scarlet iOS leverage this same enterprise certificate infrastructure to deliver apps to users. This is why you need to take an extra trust step: iOS does not automatically trust enterprise certificates the way it trusts App Store apps signed by Apple itself.

Why the “Untrusted Developer” Error Appears

When you first install an app signed by an enterprise certificate (including Scarlet iOS itself, or any app distributed through it), iOS displays an alert when you try to open it: “Untrusted Enterprise Developer.” It means the developer of the app is not trusted on your device yet. This is not an error in the traditional sense. It is a security checkpoint Apple builds into iOS to prevent enterprise-signed apps from running without explicit user consent.

Once you trust the developer in Settings, apps signed by that certificate open on your device. Apple notes that the device must reverify the developer’s certificate periodically, which needs an internet connection, and a revoked certificate stops all of those apps.

Step-by-Step: How to Trust an Enterprise Certificate on iOS 26 and iOS 27

Step 1: Install the App First

Complete the app installation normally. The app icon appears on your home screen as normal; when you tap it, the untrusted developer message appears. Proceed to Step 2.

Step 2: Open Settings

From your iPhone home screen, tap the Settings app (the grey icon with gears).

Step 3: Navigate to General

Scroll down and tap General. This opens the general device settings section where Apple places certificate management alongside other device-level controls.

Step 4: Open VPN & Device Management

Within General, scroll down until you see VPN & Device Management (sometimes labeled simply as Device Management on older iOS versions). Tap it. This screen lists all configuration profiles, MDM enrollments, and enterprise developer certificates currently installed on your device.

Step 5: Find the Certificate

Under the Enterprise App section, you will see one or more entries. Look for the certificate associated with the app you are trying to trust: this will typically show the name of the signing organization. Tap on that entry to open the certificate detail page.

Step 6: Tap Trust

On the certificate detail page, you will see the organization name, the certificate type, and a blue Trust “[Organization Name]” button. Tap it. iOS will display a confirmation dialog warning you that trusting this certificate allows all apps signed by this developer to run on your device. This is expected and intentional. Tap Trust again to confirm (on iOS 18 and later the button can read Allow & Restart). Stay online, because iOS checks the developer with Apple.

Step 7: Return to Your Home Screen and Open the App

Press the Home button or swipe up to return to your home screen. Tap the app icon. It should now open without any “Untrusted Developer” message. If you are trusting the Scarlet iOS installer itself, it will launch and you can immediately begin installing other apps.

Trusting Certificates for Apps Installed Through Scarlet iOS

When you install an app through Scarlet iOS, that app is signed by the same enterprise certificate used by Scarlet iOS itself. This means that once you trust the Scarlet iOS certificate, all apps installed through the platform should also be trusted automatically: you typically do not need to repeat the trust process for each individual app.

However, after Apple revokes Scarlet’s certificate, the newly signed Scarlet uses a different certificate, so you need to trust the new developer entry once and reinstall your apps through it.

What If the Certificate Is Not Visible in Settings?

If you navigate to VPN & Device Management and do not see any enterprise app certificate listed, the app has probably not finished installing: the Enterprise App entry only appears once an enterprise-signed app is on your device. Check that its icon is on your home screen and has finished downloading, then look again. If it is missing, install the app again from the beginning in Safari (not Chrome). For a full reinstallation walkthrough, see how to install Scarlet iOS on iPhone without a computer.

Certificate Revocation: What It Means and What to Do

Apple monitors enterprise certificate usage. When it detects a certificate being used for broad public distribution, as is the case with Scarlet iOS, it may revoke that certificate. A revoked certificate means that all apps signed with it will stop launching on every device once it checks the certificate, regardless of whether those devices have trusted the certificate previously.

When this happens:

  • Existing apps installed through the revoked certificate stop opening: they close right after you tap them, or iOS shows a message such as “Unable to Verify App” or that the app is no longer available. Their data stays on the device as long as you do not delete them.
  • No new apps can be installed using the old certificate.
  • Scarlet’s developer has to release a newly signed build, and how long that takes varies.
  • You will need to reinstall Scarlet iOS using the new certificate and re-trust it in Settings. You can get it again from our Scarlet iOS install page.
  • You may need to reinstall apps that were signed under the old certificate.

This is the single most disruptive part of using enterprise-certificate-based sideloading. Scarlet iOS cannot prevent revocations; it can only offer a newly signed build afterwards. For help when things go wrong, the Scarlet iOS not working: 10 fixes guide covers certificate revocation recovery in detail.

Tips for Managing Multiple Certificates

  • Periodically review your VPN & Device Management screen and delete enterprise apps you no longer use with the Delete App button; there is no separate button to remove only the certificate.
  • If you use multiple sideloading platforms, each may use a different enterprise certificate. Trust each one individually.
  • Do not trust certificates from sources you do not recognize or have not deliberately installed. Unfamiliar certificates in your list may indicate a compromised or unknown app installation.

Getting Started with Scarlet iOS

Trusting an enterprise certificate takes under a minute and unlocks a world of apps beyond the App Store. With the trust step complete, Scarlet iOS and every app it delivers will run seamlessly on your iPhone or iPad.

Ready to get started? Visit Scarlet iOS and install it today. The trust process is the only technical step in an otherwise seamless experience.

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