On previous versions of the connection client you could disable the startup with a registry edit (https://communities.bentley.com/communities/other_communities/sign-in_assistance_and_web_services/f/cloud-and-web-services-forum/124438/disabling-or-turning-off-the-bentley-connection-client-sign-in-dialog-box)
With this version, it appears to have added another registry item at HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\Bentley License Service
Despite having a GPO to delete it, it reappears on every login. Is anyone having a similar issue?
Delete this key
HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\Bentley License Service