Clients may boot to Next Boot Device and/or a PXE Boot Menu is missing previously existing boot options. The PXE Configuration Utility is also missing the same options.
Unknown root cause. Result is corrupt preboot configurations and/or PXE Manager corruption.
If a backup of the server exists, stop the services and restore the PXE folder (default is C:\Program Files (x86)\Altiris\eXpress\Deployment Server\PXE) from the backup or restore the entire server. If the server is a VM, reverting to a recent snapshot is also an option. Lastly, recreate the Preboot Configurations using the PXE Configuration Utility.