The random failing of the Load Generators that have the Agent set to run as a process will fail if the user who logs in manually logs off, or a security policy forces a log off. Please work with your security team to ensure that the system user logged on is not logged out.
The following Knowledge Base article was published by Micro Focus and explains the reason why some protocols require the Agent to be run as a process:
* Document ID: KM182623
* Micro Focus Product(s): Performance Center
What is the difference between running the Performance Center Agent as a process versus a service?
The Performance Center Agent differs between service and process in the following ways:
Running the Agent as a process requires you to log into the machine in order to connect to it as a Load Generator. The Agent service does not require login, but the system needs to be booted.
The Performance Center Agent service is started in the background as and when system is booted like any other service at windows OS level.
2. Vuser limitation:
The Agent service cannot run GUI, or GUI-like scripts (TruClient, Citrix, SAPGUI), etc.. This is due to the constraints that the operating system puts on services when they run. The Agent process does not have such limitations. It is only limited by the permissions of the user who is logged in.
In light of the KB article referenced above, there is no other option except to run as a process.
I hope this helps