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.
Screensaver on Mac (Yosemite) - takes over 30 seconds to load
I'm testing iScreensaver Designer version (v126.96.36.1998), and when I try to create a screensaver, all I get is a black screen for 30 seconds before the screensaver loads. I'm using Flash CC on a Mac, running Yosemite (10.10.5). iScreensaver acts like it builds it successfully, and when I look at the screensaver window in my Preferences, the small preview window plays correctly. Unfortunately, when I try to run the screensaver, it takes so long to load that I didn't think it was playing at all.
My Flash movie is a simple timeline-based animation with no actionscript.
I read in your Guide that for users of Flash CS, they need to export their .swf as v9. The lowest Flash Player version that I can export from CC is 10.3. Could this be a problem? Are there any other settings in Flash I need to know about?