I developed an app in Eclipse, and emailed to me the .apk file. It correctly downloads to my phone, then I go in Downloads and tap it. I choose "Install" and I'm getting App not installed message.

What's the problem?

I have a Nexus 4 phone, and "Unknown sources" option is selected. I can successfully install the app through Eclipse. The .apk file was exported in Eclipse from Android tools -> Export unsigned application package.

3 Answers 3


Android does not allow installing unsigned applications. You will need to sign you APK (with a debug or release key). Don't use Android tools->Export unsigned application package, but rather the regular command to export an Android APK.

The different options available to sign you app are well described here: http://developer.android.com/tools/publishing/app-signing.html


The apk file is also generated in the bin folder of the project after running the app at least once.

I've copied the apk file from the bin folder and installed it successfully on three different phones without any problem both copying directly on phone memory or sending it via email.


Do you already have the application installed on your phone (installed via Eclipse)? If so I expect the exported apk is signed with a different key to the version already on your phone. Android will not allow you to 'update' an app if the signing key is different.

Un-install the app and try installing the apk again. If it still fails it may be that the exported app is corrupt in some way.

  • Yes, I already have the app installed. However, the exported app was unsigned. I tried to uninstall it, and install it again from .apk. It doesn't work. I've tried to install it also on a Galaxy S3 phone of a friend and I've got the same message. How can it be corrupted if I exported it using Eclipse, and launched from Eclipse it works? However I exported it again to be sure and doesn't work...:(
    – blackwolf
    Mar 6, 2014 at 11:29
  • 4
    @blackwolf There are no unsigned apps in Android. If you haven't signed the app with a release key, it's signed with a "debug key", specific to the machine it was built on.
    – Dan Hulme
    Mar 6, 2014 at 12:11
  • 2
    @DanHulme I think you are wrong. Android tools->Export unsigned application package does exactly what it says: create an unsigned APK. This is the reason it cannot be installed on a device: it's not even signed with the debug key.
    – Sébastien
    Oct 7, 2014 at 8:47
  • @Sebastien I see what you're getting at. Yes, that seems the most likely explanation.
    – Dan Hulme
    Oct 7, 2014 at 8:58

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