When I run an android app from eclipse I meet this error and my app does not start:
Installation error: INSTALL_FAILED_MEDIA_UNAVAILABLE
In my case
1 - uninstall some Useless/low use apps
2 - clear ram memory
this worked for my device: I had tried installing the apk through various means (adb install, installing it using the installer app, as well as the advice here) only to find that the solution was related to an app called Twilight, which once uninstalled, I was able to install apks again. I found the solution here. If anyone can shed light on how an app can block installs like this did, that would be much appreciated.
It's can be because of low memory. For me problem solved when delete some unnecessary files and apps.
In my case the solution was to restart the phone.