Fix “App Not Installed” in Flutter

If you’re facing the “App not installed” error when trying to install a release build of your Flutter app on an Android device, there are a few potential solutions.

• First, try uninstalling any previous versions of the app from the device. If that doesn’t work, make sure that you’re using a compatible device; the app may not be able to be installed on older devices. Android doesn’t allow the same package name but a different key app to be installed twice. So you need to delete the old app and then install the newly built apk file.
• Check if your device is out of storage. Depending on the size of the app, you may just need to free up some space on your device. An app typically requires at least twice the space of its APK package, plus the total uncompressed space consumed by the app’s files. So if you’re trying to install a 100 MB app, you’ll need at least 300 MB of free space on your device. Once you’ve cleared some space, try installing the app again. With any luck, it will now go through without any problems.
• Allow “Install App from Unknown Sources.” When you want to install an app from anywhere other than an official app store, your device needs to be able to allow installation from unknown sources. This is because apps from outside of official app stores haven’t been vetted in the same way that apps from official app stores have. They may not be as safe and secure, and they may not adhere to the same standards. Since we are about to install an apk file, it is required to set the device to install an app from an unknown source.

If none of those solutions work, it might be because your device is not compatible with the app. In that case, you will need to find an alternative app that is compatible with your device.