SYMPTOMS:

When you install HP Lights-Out Passthrough Service at a Terminal Server (which means you have RDP Service enabled for multiple users) you receive following errors:

• In installer: Service ‘HP Lights-Out Passthrough Service’ (hplopts) failed to start. Verify that you have sufficient privileges to start system services.
• In Application Log: The Passthrough Service could not be started. You must install Terminal Services or enable Remote Desktop.

SOLUTION:

This happens because of weird prerequisites check.

Set registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\fDenyTSConnections = “0”. Installation should succeed.