>>I'm pretty sure that VFP works with UNCs.
>
>Yes, definitely with NetBIOS-style UNCs e.g. \\NetBIOSServerName\ShareName\FolderPath\FileName .
>
>However, the OP is seeing issues with internet/FQDN-style UNCs e.g. \\MyServer.MyDomain.com\ShareName\FolderPath\FileName .
>
>I don't have an easy way to test the latter so I'm speculating that VFP doesn't support it internally, even though Windows itself does, and it might be used by the OP's customer to start his app.
>
>Do you know for certain that VFP fully supports internet/FQDN-style UNCs?

No, I don't know about FQDNs. I can't even get my windows 10 to use a local shared folder I created and I can't even get to C$ or D$. I guess I don't what the hell I'm doing today.