I frequently run into this too, where I have to kill Dorico in the task manager before it will start. However, after reading this post, I didn’t bother saying anything, as I use both a 3rd party internet content filter, and McAfee security software. I just figured one of those is likely to blame, and it’s so easy to kill it that it’s hardly worth my time tracking down the cause of the issue.
A search of the forum brings up numerus threads related to this.