Cache ^%GI [unavailable] Cannot import from THIS device

Working with a client who has two TryCache instances on his W10 machine. Trying to bring in globals from a text file which works fine in my environment but on his, he cannot make ^%GI accept a file from his C drive. His Cache is on C as is mine. Checking the path and the file name carefully, it is accurate. D ^%GI and enter the path with filename (as works fine for me on my system) and he gets a message [unavailable] and when he hits enter out of that message, he sees Cannot import from THIS device. I think I'm missing a config or security setting of some kind but I don't know what it is. Thanks for any ideas.

John Jacobs