Warning message from "Show in Explorer"

When I left click an html file in the Project pane and select “Show in Explorer” from the drop down, a yellow warning message appears on the right side of the screen with the message “Unable to Show” with the file path. It then disappears in a second or so and then File Explorer opens at the requested file. What causes this?

sounds like an issue concerning mod-rewrite file… what is the ext of your domain name or target object