Cannot install the Exchange 2013 Management Tools after Removing the Exchange 2010 Management Tools.

Scenario:  When attempting to install the Exchange 2013 Management Tools, the Exchange 2013 setup GUI shows the Management Tools as checked and grayed out even though the Exchange 2010 management tools are no longer installed on the computer.

Resolution:  Install the Management Tools from Powershell. From the Exchange Install directory, execute the following:

.\setup.exe /Role:ManagementTools /IacceptExchangeServerLicenseTerms