You may need to download the bootable recent version from here....
https://support.apple.com/techtooldeluxe/main?id=dl
TechTool Deluxe from Micromat is a powerful diagnostic utility that allows you to test your computer's critical system components, such as the processor, RAM (random-access memory), VRAM (video random-access memory), the hard disk, and more. TechTool Deluxe can also repair your computer's disk structure and rebuild its directories as necessary.
TechTool Deluxe is only available with an AppleCare Protection Plan. If your Mac is currently covered under the Apple One-Year Limited warranty and you would like to extend your world-class telephone technical support and hardware repair coverage to three years from your computer’s date of purchase and get TechTool Deluxe, purchase an AppleCare Protection Plan today.
If you purchased AppleCare Protection Plan for your Mac and need to download the latest version of TechTool Deluxe, please enter your serial number below so that we can validate your coverage.