• This is most likely the most prevalent cause of the App not installed problem. It's because the apk file you downloaded is corrupt on its own. This could be because some data packets were missing when you downloaded the software (due to a bad internet connection, for example) or because the apk file on the site was corrupted.
• To avoid such issues, make sure you download the programme from a reputable and secure source first. Don't go any farther in the search results since you can end up with a rogue software that can harm your phone.
• Installing an app from an SD card or from within a directory can sometimes cause problems during installation (particularly in previous versions of Android). So, all you have to do now is move the apk file you downloaded to the root directory of your device (within internal storage and not in any folder). Then try again to install the software.

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