To resolve this issue, perform the following steps:

1. Reboot the appliance.
2. At the bottom of the splash screen, in the space provided after "Boot Option," enter the following line

init=/bin/sh

3. Press Enter to save and b to boot.  The init=/bin/bash statement boots straight into a shell, so no password is required. Running fsck and other maintenance tasks may now be performed.
4. Type:

fsck -y /dev/sda1

5. Reboot the virtual appliance:

reboot

The system will now boot normally without asking for the root password.