Short version: there's a known bug with the fprintd package that ships with Fedora 17. If the VM you're using for Fedora doesn't have a USB controller added to it, fprintd will crash and halt your system.
- Restart the VM.
- At the boot loader, select Advanced Options for Fedora Linux.
- On the next screen, select the option with (recovery mode) at the end.
- You'll see a system prompt with root@hostname; this is your recovery console.
- Run this command: yum -y remove fprintd
- When fprintd is gone, reboot the system.
Your VM will now boot without any complaints.
However, if you need fprintd, there's a fix for that, too. Remember that fprintd wants a USB controller at system startup. So give it one:
- Right click your fedora VM and choose Edit Settings...
- On the hardware tab, click Add...
- Highlight USB controller and click Next.
- Select the type of controller you want (if you're not sure, take the default).
- Click Next to review your settings, then click Finish.
- Click OK to commit the change.
Your VM now has a USB controller. Restart your VM, and fprintd will load properly, which means Fedora will load properly.