Sideloaded App Not Opening on iPhone? Every Cause and How to Fix It

You tap an app you installed outside the App Store and nothing happens. Maybe it flashes open and closes, maybe iOS shows a message, maybe the icon just sits there greyed out. It's frustrating, especially if the app worked fine yesterday.

The good news is that a sideloaded app that won't open almost always has one of a handful of causes, and each one has a simple fix. Work through the list below in order - the first few cover most cases.

First, read the message

What you see when you tap the icon tells you a lot:

• "Unable to Verify App" or "no longer available" - the signature has expired or been revoked. See section 1.
• "Untrusted Developer" - iOS hasn't been told to trust the Apple ID that signed it. See section 2.
• "Developer Mode Required" - Developer Mode is off. See section 3.
• The app opens and immediately closes - usually a signing problem, an iOS update or a broken install. See sections 4 to 6.
• Nothing at all, or the icon is dimmed - see sections 5 and 7.

1. Check whether the app has expired

This is the most common cause by far. Every app on an iPhone has to be signed. Apps from the App Store are signed by Apple. Apps you install yourself are signed with your own Apple ID, and with a free Apple ID that signature only lasts 7 days.

Once the 7 days are up, iOS refuses to open the app. Nothing is wrong with the app itself - it just needs signing again.

To fix it:

1. Connect your iPhone to the computer you installed the app with.
2. Open the same sideloading tool you used the first time.
3. Install the same app again with the same Apple ID.

Re-signing the same app keeps its data, so you won't lose anything. If you want the full picture, including the 3-app and 10 App ID limits, read why sideloaded apps expire after 7 days.

2. Trust the developer

The first time you install an app signed with a particular Apple ID, iOS blocks it until you say you trust that account. You'll see an Untrusted Developer message.

1. Open Settings → General → VPN & Device Management.
2. Under Developer App, tap the Apple ID the app was signed with.
3. Tap Trust, then confirm.

Your iPhone needs an internet connection for this step, because iOS checks the certificate with Apple. If Trust doesn't seem to stick, connect to Wi-Fi and try again.

You only need to do this once per Apple ID, but if you delete every app signed with that account, iOS can forget the trust and ask again next time.

3. Turn on Developer Mode

Since iOS 16, apps installed directly onto an iPhone won't run unless Developer Mode is on. If it's off, tapping the app shows Developer Mode Required.

1. Open Settings → Privacy & Security.
2. Scroll to the bottom and tap Developer Mode.
3. Switch it on and tap Restart.
4. After the restart, unlock your iPhone and tap Turn On.

If you can't find the switch, it's usually hidden until a developer app is installed. Our Developer Mode guide explains why it goes missing and how to make it appear.

4. Check the signing certificate hasn't been replaced

A free Apple ID can only hold a small number of development certificates. Some sideloading tools create a new certificate when you sign in, and that can revoke the old one. When that happens, apps you signed earlier stop opening, even though their 7 days aren't up.

This often catches people who use two tools with the same Apple ID, or who set up a second computer.

The fix is the same as for an expired app: reinstall the affected apps with the tool you use now. To avoid it in future, stick to one tool and one computer per Apple ID where you can.

5. Restart after an iOS update

iOS updates are a common trigger. After an update, a sideloaded app may refuse to open or close straight away until things settle.

Try these in order:

1. Restart your iPhone.
2. Check Settings → Privacy & Security → Developer Mode is still on.
3. Check the developer is still trusted in Settings → General → VPN & Device Management.
4. Re-sign the app with your sideloading tool.

If the app still crashes, the version you have may not support the new iOS release yet. Look for an updated build from the app's developer and install that instead.

6. Reinstall a broken install

Sometimes an install simply goes wrong - the connection drops partway through, or the computer goes to sleep. The icon appears, but the app won't launch.

Install the same app again over the top with your sideloading tool, keeping your iPhone unlocked and connected until it finishes. Installing over the existing app keeps its data. Only delete the app as a last resort, because deleting it removes its data too.

7. Rule out Screen Time and storage

These aren't specific to sideloaded apps, but they're easy to miss:

• Screen Time limits: if an app limit or downtime is active, the app shows as dimmed or opens to a time limit screen. Check Settings → Screen Time → App Limits.
• Low storage: if your iPhone is almost full, apps can fail to launch. Check Settings → General → iPhone Storage and free up some space.

If the app needs a helper to work

Some sideloaded apps open fine but then can't do their job, which can look like the app is broken. Location tools and apps that refresh themselves on the phone often rely on LocalDevVPN to reach the iPhone's own developer services. If that's off, or another VPN is running, the app may open but report that it can't connect. See what LocalDevVPN does and how to fix it.

How Mirrage avoids most of this

If the app you're having trouble with is Mirrage, most of these problems are handled for you. The one-time setup, about 5 minutes with a Mac or Windows PC from the download page, takes care of trust and Developer Mode. After that, Mirrage re-signs itself on your iPhone before the 7 days run out, as long as LocalDevVPN is on, and Settings → App refresh inside the app shows how many days are left.

If the signature does run out completely, iOS won't open the app at all - so Mirrage can't fix itself from there. Plug in, run Mirrage Setup again, and your data is kept.

Once it's running, you can Teleport to a single spot or start a Journey that walks or drives along real roads, and tap Stop to return to your real location instantly.

FAQ

Why won't my sideloaded app open anymore?

The most likely reason is that its 7-day signature from a free Apple ID has expired. Re-sign it with the same tool and Apple ID you used to install it, and it will open again with its data intact.

How do I fix "Untrusted Developer" on iPhone?

Go to Settings → General → VPN & Device Management, tap the Apple ID under Developer App and tap Trust. Your iPhone needs an internet connection for this to work.

Why does my sideloaded app open and close straight away?

It's usually an expired or revoked signature, Developer Mode being off, or a version that doesn't support your iOS release. Check each in turn, then reinstall the app with your sideloading tool.

Do I lose my data if a sideloaded app stops opening?

Not if you reinstall the same app over the top. Re-signing keeps its data. Deleting the app first does remove its data, so avoid that unless nothing else works.

Do sideloaded apps stop working after an iOS update?

They can. Restart your iPhone, check Developer Mode and developer trust are still on, then re-sign the app. If it still crashes, look for a newer version that supports the update.