I spent a little while today trying to work out why the emulated SD card wasn’t mounting in my virtual android device. I’d used AVD Manager to configure a 100MB SD card for one of my AVDs and the file was created on the host system, but having started the AVD up the card wasn’t mounting.
A bit of googling finally took me here. Sure enough, when I opened by config.ini, the sdCard setting was configured to “no”.
Changing that to “yes” and re-starting the AVD had the desired effect.