How to disable FortiClient from auto run?

I and others have no need for FortiClient to start automaticly when the PC is turned on. But how to disable that autorun?

In FortiClient itself there is no such feature, there is no AutoRun in Windows Registry and trying to disable it in Windows Services gives the error "The parameter is not correct". And there is also no mention of it in the Autorun tab in the Windows TaskManager.

We only need it when we need it, so there is no need at all to keep it running in the background.