I just installed an SSD (and kept my hard drive). If I hold down the Option key at bootup, the hard drive and the SSD show up as boot options and I can boot to the SSD. However if I go into System Preferences->Startup Disk, only my hard disk shows up. Finder and disk utility also show the SSD. How can I boot to the SSD without going through the Option key each time? Mavericks on a mid-2011 21.5" iMac. Thanks.