Android Installation failed - Same package but a different signature

Question

I have my release app (from Google play ) installed on the device. When I am trying to install the app via run in Android studio , I get this error .

I changed nothing ,It always worked, I always checked the release version before uploading the apk to Google play .

I thought maybe uploading to Google play will resolve the issue so I uploaded an alpha version (didn't want to take the risk of uploading to production so my users won't be enforced to uninstall first) But my alpha testers get this:

, I believe that if I upload the apk to production it will be the same.

1. What could lead to the difference in the signatures?
2. How can I check what is the difference?

Answer 1

So let's answer your question in reverse order.

2. How can you check the difference?

You can check the difference by pulling the APK off the device, then looking at the certificate hash.

1. What could cause it?

Lots of things - here's two:

• you changed your local keystore (or deleted it) and Android Studio generated you a new one
• you enrolled in Google Play App Signing so the signature on the delivered APK is different from the signature on the APK you uploaded.

Answer 2

Even if you have the same package, if you have a different buildType the phone won't allow it to install without uninstalling the previous version.

I had the same issue with HockeyApp, and uninstalling the existing version on the phone fixed it.

Answer 3

You have a signed release version already installed on your device, Thus you can't install an unsigned debug version.

My solution is to uninstall current package from device (and also clear it's data to make sure) and then retry running via android studio.