Think I am going in circles so asking the hive mind.

Trying to get SCCM to shutdown on a schedule. When I set the shutdown a Security Warning box appears on the target machine. It is running from c:\windows\ so shouldn't be a IE remote file issue, but I have added the domain to trusted sites to make sure. I have disabled UAC through GPO to try and discount that, no luck. Why is a local file coming up as untrusted and how can I get round that?