What is Unknown Sources?

Unknown sources define places outside the Google Play Store from which you downloaded an apk app. Google considers its own Play Store as the only trusted source for apps to be installed on Android.

However there are situations when you need to download unknown sources, such as apps coming from third-party marketplaces or apps that are currently in beta-testing phase. Platforms such as Appaloosa enable app distribution outside the Play Store and require such permissions. Such distribution method is also known as sideloading.

Since the early Android operating system versions, users have to explicitly approve unknown sources to be enabled in settings.

So if you are trying to install a downloaded apk without this setting enabled, you will be prompted with this message:

For your security, your phone is not allowed to install unknown apps from this source.

unknown sources on Android

How to enable Unknown Sources in Android?

To allow apps to be downloaded from Unknown Sources, follow the steps below

For old Android versions (4.0, Lollipop 5.0, Marshmallow 6.0, Nougat 7.0)

  1. Go to your Android Settings > Security
  2. Check the option Unknown sources
  3. Tap OK on the prompt message
  4. Select Trust

enable unknown sources

If you are running Android 9.0 and later, you will need to allow Unknown sources for each app willing to install an apk file. For instance if you are using two browsers such as Chrome and Firefox, you will need to allow both Chrome and Firefox to install unknown sources.

For New Android Versions (Oreo, Pie, Android 10, 11 and 12)

  1. Go to your Android Settings > Apps & Notifications
  2. Select Advanced or the three dots at the top-right corner – users might see either option depending on their device
  3. Select Special App Access
  4. Choose Install Unknown Apps
  5. Select the apps you want to allow to sideload apk files