>>>When a built-in function like DIRECTORY(), FILE() or FCREATE() is passed a UNC-path that does not (no longer) exist, it takes a very long time to tell you that. Is there an API function that can tell this much quicker?
>>
>>What is "a very long time"?
>
>A minute.

Check your DNS setup. I can see both existent and none existent shares in under 2 seconds across a WAN.