Unable to install apk Android

Hi ,

I am developing a game with unity 4.3.3f1 Android platform using unity free.

When I try to install the game on Samsung Galaxy S3, I have no problems, but when I try to install it in another phone, it tells me “Unable to install”

How can I fix?

You can try lowering the API level.

Also if the processor in your device is ARMv6 instead of ARMv7 it will not work neither.
Unity filters all the devices with ARMv6.

Also check if the app you are trying to install is of the same name as an existing app previously installed. Sounds silly, but i had this issue. and It took me really long to find out.