Periodically, packages deployed using NS7 to newly installed agents that have not been rebooted yet may fail with an Exit code of 1618.
This is caused by a hung instance(s) of the MSIEXEC.EXE service (this is the Windows Installer component used to install deployed MSI packages). It is likely that you will see multiple instances of this process in process explorer.
In order to resolve this deployment issue and expedite the installation of the packages in a failed state, simply end all of the processes using the MSIEXEC.EXE service (make sure you're NS7 agent is not currently installing any packages, and that you are not installing any software outside of the agent). After terminating all instances of the MSIEXEC.EXE process, attempt to run the installation of the failed package again and it should succeed.