Android System Installer App "Application Not Installed" why? where is log for this?

Issue

I am trying to install an unsigned apk by placing in download directory.
Installer comes up and has a few warning like allow to modify properties etc.
I click on install and it just says Application Not Installed?

What is the possible reason for it and in what log file would the installer tell me the problem.
Where is this log file?

Thanks

Solution

It could be possible that the same application was already installed over to the device but with different computer and now you are trying to install the same unsigned app from your computer.

SOLUTION 1 : uninstall that installed application. SOLUTION 2 : Sign the application and try to install

This actually happens with the unsigned apk file because for the unsigned apks, android uses the debug.keystore which is different from computer to computer.

Answered By - Rohit Mandiwal