How to Fix App not installed problem on Android. The apk file that you are trying to install can have a default setting applied to it, which is not adjusting with your phone and you are unable to install the application. By using the third-party apk editor you can change those settings and make it a better match for your phone without any issues. 1. Download APK Editor Pro ⬇ Download ( Free) ⬇ Download (Play Store) 2. Once it’s installed, Open the application 3. Now click “Select an APK File” 4. Then locate the apk file, which you want to install and select it 5. Select “Common edit” in the list of editing 6. You will find an option there “Install location” 7. Press that and select “Internal Only” 8. press "Save" 9. Now you can see a Green Tick.Then you press "Install" That's it Now the "App not installed" problem was solved. Still you have any doubt you can check this video Conclusion . This is the main way...