'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

The "Application not installed" error can also occur if the app has been installed to or moved to the SD card, and then the USB cable has been connected, causing the SD card to unmount.

Turning off USB storage or moving the app back to internal storage would fix the issue in this case.