This Knowledgebase article provides information about what to do if the NT Backup window is closed during the Neverfail Heartbeat installation process.
When installing Neverfail Heartbeat on a server pair, the Setup process takes a backup of the Primary server using NT Backup. This is then restored to the Secondary server during the setup process. If the NT Backup window is closed or the 'Cancel' button is clicked while the restore is being performed on the Secondary server, the setup program does not detect this or display any error and the installation will appear to be finished successfully despite the fact that the restore has not completed.
Neverfail strongly recommends that the restore be allowed to complete during the installation on the Secondary. If the restore does not finish completely please contact Neverfail Support.