If you have security software blocking Pega Robotics, this is likely caused by an update to Windows 10. This has been resolved in later versions of both SP1 and 19.1. I would suggest trying to install the latest version as that is most likely going to resolve the issue.
I would suggest opening a support request as we'll need to get hands on with your machine. 19.1 would still present the issue if security software were blocking our process from injecting into IE. One other thing to check is to see if IE Protected mode is enabled.
If you do open a support request, please report the SR Number here, so we can add the resolution to this post.