Exchange 2013 Recovery Mode
After a failed install, or if you encounter an inconsistent state in Exchange that prevents it from starting, you may have to re-install Exchange Server 2013 using recovery mode.
Disable UAC on the Exchange server.
Open PowerShell and navigate to the setup file location.
Execute the following command:
.\setup.exe /m:recoverserver /iacceptexchangeserverlicenseterms
the recoverserver switch will rebuild Exchange using the parameters stored in Active Directory.