Here is our problem: The disk drive was / is failing on a MacBookPro. I backed up all our important files to an external hard drive. Stupidly we DL'ed the Maverick update. Now all I get is OS X cannot be installed. HD is damaged and cant be repaired. So, went out and got a new HDD. So, I do still have access to the Disk Utility and Terminal with the old drive. Thought I'd do a clean install of Maverick. I found a copy of Maverick and DL'ed it on my only other computer, a PC. Put the dmg file on a USB drive formatted in ExFat because the file is over 5GB and communicates with PC. Formatted another USB drive using the Disk Utility in Mac OS Extended (Journaled) and GUID Partition Table. Used Terminal to copy the maverick dmg file to the GTP USB drive. Put in a new HDD and boot holding options. I get nothing. Just an arrow. I cant figure out how to boot Maverick and format the new drive with a failing old Mac drive, new HDD, a PC, and two USB drives. Oh, and five dogs, but they are no help.