I have iMac with a dock and a SSD drive in it. I cloned the old interior drive to the sad in the dock. All was well until I saw on you tube be puttingYosemite on a usb drive. Somehow I made a mistake and system went back to the older interior drive which was about 3 weeks older than the ssd drive. All along I was backing up the sad drive to Time Machine. Now after formatting the sad drive it cannot find WD drive that has time machine.How do I restore my sad drive with the Time Machine drive as it is not seeing it.