'App not Installed' Error on Android

Question

I have a program working in the Android Emulator. Every now and again I have been creating a signed .apk and exporting it to my HTC Desire to test. It has all been fine.

Answer 1

My problem was that I have multiple user accounts on the device. I deleted the app on 1 account, but it still was installed on the other account. Thus the namespace collided and did not install. Uninstalling the app from all user fixed it for me.