At the present time, iScreensaver Designer 5.2 provides support for macOS 10.13 High Sierra, but there are some functional limitations.
Please read the 10.13 High Sierra Tech Note
as well as the Release Notes
Due to changes made by Apple, iScreensaver Designer version 5.2 does not currently support macOS 10.14 Mojave.
Please read our forum post
for the latest updates.
[Solved] "Check Plugin Version" when not using plug-ins?
If I create a video screensaver and the "Check Plugin Versions" feature (of iScreensaver 5.0) is enabled for Flash and OpenGL, as is the default setting, will the installer check these plug-ins regardless of whether I actually employ them or not? If I only use video in a project, should I toggle off "Flash" only, or also "OpenGL"?