In my lab, while installing Exchange 2013 on another server, the following error was thrown:
“The Registry Key “Software\Microsoft\ExchangeServer\V15\Transport” does not exist under “HKEY_LOCAL_MACHINE””
![Exchange 2013: client access role install error Exchange 2013: client access role install error](https://www.collaborationpro.com/wp-content/uploads/2016/09/cas1-300x261.jpg)
Navigating to that registry key, sure thing that the key doesn’t exist.
Solution:
Right Click V15 and add a new Key and call it Transport. Exit the setup and start it again and it should complete.
Hope it helps.