we are not able to save changes to TIs from Arc when running as a service. If we run the executable file, it works as normal for the same user. User is an admin to the server.
Edit: Saving a TI within the server works well (Using both local host and fully qualified path).
The only difference I would see between running arc.exe and running Arc as a service would be the security on the server. You could try to set up an admin account to run the Windows service instead of using Local System, try to use the same account which is running the TM1 services.
This is a bit odd, it is your TM1 session creating the process but I can see that a support ticket has been created, we’ll investigate this on the ticket and we’ll post the solution here.
Could you please create a new issue in GitLab, so you could upload files and add your comments there? I would like to see HAR files from chrome network tab (Dev Tools) after you save a process or rule.