Fix “This App Cannot Be Installed Because Its Integrity Could Not Be Verified”
“Unable to Install: This app cannot be installed because its integrity could not be verified” is one of the most common errors when you sideload an IPA on an iPhone or iPad. It means iOS checked the app’s signature and rejected it, so the app never installs. This guide explains what the message means, the usual causes, and the fixes in the order worth trying. Last checked: October 27, 2026.
The Short Version
- The error comes from iOS itself, not from Scarlet or another installer. It means the app’s code signature or provisioning profile is not valid for your device.
- The most common causes are a revoked certificate, a device that is not registered in the signing profile, a damaged or badly re-signed IPA, and the free Apple ID app limit.
- It is different from “Unable to Verify App” (shown when you open an app already installed) and “Untrusted Developer” (an app that installed but is not trusted yet).
- Re-downloading and re-signing the IPA fixes most cases. If the certificate itself is revoked, no setting on the iPhone fixes it.
What the Error Means
Every app on an iPhone must be signed, and the provisioning profile inside it says which devices may run it. When you tap Install, iOS checks the signature against the files in the app and against the profile. If anything does not match, or the certificate is no longer valid, iOS stops the install and shows this message. The SignTools project’s FAQ sums it up simply: the error means the signature is invalid, so check that the signing profile is valid and that your device’s UDID is registered in it.
That also explains why it can appear suddenly for an app that installed fine before: the app did not change, but its certificate or profile did.
Common Causes
| Cause | Typical sign | Fix |
|---|---|---|
| Revoked certificate | Every app from the same installer fails at once | Wait for a new certificate, or use another signing method |
| Device not in the profile | Works on one device, fails on another | Register the device UDID and re-sign |
| Damaged or edited IPA | Only one app fails | Re-download from the original source and re-sign |
| Free Apple ID limit | Happens with the fourth app in SideStore or AltStore | Remove or deactivate an app first |
| Download or network problem | Fails once, works on retry | Retry on a stable connection |
How to Fix It
1. Retry once on a stable connection
An interrupted download leaves a broken app package, and the signature check then fails. The SignTools FAQ notes that “Unable to Install” can be a network problem, so try again first: turn Wi-Fi off and on, or switch between Wi-Fi and mobile data, and install again.
2. Check whether the certificate is revoked
If every app from your installer fails at the same time, or the installer itself stops opening, the certificate behind it has most likely been revoked by Apple. Apps signed with a revoked certificate cannot be installed, and changing iPhone settings will not help. With shared-certificate installers such as Scarlet iOS, the fix is to wait until the installer switches to a working certificate and then reinstall; see what to do when the certificate is revoked. If revokes keep happening, a method that uses your own Apple ID, such as SideStore, avoids shared certificates.
3. Re-download the IPA and sign it again
If only one app fails, the IPA itself is the usual problem: a corrupted download, a file someone edited after it was signed, or a build re-signed incorrectly. Delete the half-installed app if its icon is on the Home Screen, download the IPA again from its original source, and install it again so it gets a fresh signature. If the source publishes a checksum, compare it first; our guide to fixing app signing errors shows how, and how to scan IPA files for malware covers checking files from unknown sources.
4. Make sure your device is in the profile (own certificates)
If you sign with your own paid developer account or a certificate you bought, the provisioning profile must include your device’s UDID (see how to find your iPhone UDID). A new iPhone, or a device added after the profile was made, will show this error until you register it, create a new profile and sign again. A developer on Apple’s forums fixed the same error on a new device exactly this way: by registering the device in the provisioning profile.
5. Stay within the free Apple ID limit (SideStore and AltStore)
A free Apple ID allows only 3 active sideloaded apps at a time and 10 app IDs per week, including SideStore or AltStore itself. When you are at the limit, a new install fails. Deactivate or remove an app you do not need, then try again (see how to fix the 3-app limit error). If you need more than 3 apps, LiveContainer can run several apps inside one slot.
6. Turn on Developer Mode if iOS asks
On iOS 16 and later, apps signed with a development certificate need Developer Mode to open. If iOS prompts you, turn it on in Settings > Privacy & Security > Developer Mode and restart. Our Developer Mode guide explains when you need it.
7. Get the detailed error with a computer
If nothing above works, the SignTools FAQ suggests installing the signed IPA from a computer with the free libimobiledevice tools (ideviceinstaller -i app.ipa), which prints a more detailed reason than the iPhone does. That tells you whether the problem is the profile, the entitlements or the files.
Errors That Look Similar
- Unable to Verify App: the app installed but iOS cannot check its certificate when you open it, often because of the internet connection or a revoke. See how to fix “Unable to Verify App”.
- Untrusted Developer: the app installed, but you have not trusted its developer yet. See how to fix the Untrusted Developer error.
- Stuck on “Waiting” or “Installing”: the install never finishes. See what to do when a sideloaded app is stuck installing.
- Requires a newer version of iOS: the app was built for a newer iOS than your iPhone runs. See how to fix “requires a newer version of iOS”.
- App crashes on launch: the app installed and opened, but quits at once. See the crash-on-launch fixes.
FAQ
Is my iPhone broken or blocked?
No. The error is about one app’s signature, not your device. Apps from the App Store and other correctly signed apps keep working.
Does restarting the iPhone fix it?
Sometimes, when the cause was a temporary download or network problem. It does not fix a revoked certificate, an unregistered device or a broken IPA.
Can I bypass the integrity check?
Not on a normal iPhone. The signature check is part of iOS security, and the only real fix is a valid signature for your device.
Why did the same app install yesterday?
Most often the certificate it was signed with was revoked in the meantime, or the installer gave you a different, broken build. Try another app from the same installer: if that fails too, it is the certificate.
For more fixes, see the Scarlet iOS troubleshooting master guide.