DiskSpy is an application that displays hard drive activity. As the developer states on the product webpage...
— Can I make it run on High Sierra ?
DiskSpy is a Windows only application, which means that it won't run on other operating systems. The only way to run the program while using an Apple product with High Sierra installed is through... virtualization.
Install a compatible version of Windows (preferably Windows XP) using Parallels Desktop and then transfer DiskSpy. Read more