My upgrade went fine, but my wife's upgrade hosed her hard-drive, and we had to wipe and start over, installing from a thumbdrive. We both have late 2013 MBPr's

My upgrade went fine, but my wife's upgrade hosed her hard-drive, and we had to wipe and start over, installing from a thumbdrive. We both have late 2013 MBPr's. The apple support person was really nice, but failed miserably to help us even build the bootable drive (they didn't understand how to use Disk Utility to create a GUID partition, or how to use Terminal to install the OS)