Not that it is a solution, but the help file says this can happen with the test button. One solution while not ideal is to not run as a service:
Note that when testing, the action set runs in the console UI process. If you are running Blue
Iris as a service in the background, “real” action sets run in the service process, and this can
create discrepancies in what you experience:
• The service has no access to the Windows UI, meaning there are no visible windows.
• The service may have limited access to some hardware, which in some cases will include
access to the sound card to play sounds.
• Popup toast actions will only appear when the console is open.
• The service by default runs as a user called “local service” which does not have the same
access to the system as your user account. For most action types, it’s recommended that
you run the service with your own user account instead. This is changed by opening the
Windows service manager (search for services) and edit the Blue Iris service entry Login
page. See the Administration chapter for instructions.
• The service may not understand your file system designations like “H:” etc. as these are
user-specific. You should always use UNC names where possible (\\server\share). “