Hey @Ian_Robertson,
Thanks for writing in and for sharing your report. @Suedkiez is quite correct with the above information, but thank you for reporting your findings no matter!
Here is more information on Roon with antivirus software:
You may be running into a slightly different issue with the latest Roon update, here’s more information surrounding what other windows users are facing:
The short-term workaround is to disable Smart App Control, the new Windows AI security features that works in concert with the Microsoft Defender firewall to statefully police network-dependent apps. Take this step if only you are willing, although the Defender firewall will remain active either way. To turn off Smart App Control in Windows 11, open the Start menu, search for and open Windows Security, click App & browser control, select Smart App Control settings, and change the option to Off
Let me know if this helps your case. 