macOS Gatekeeper blocking the app (common if the DMG wasn’t downloaded recently from the App Store). Fix:
If you already have a genuine DMG file for iMovie 10.2.5 (e.g., from a trusted backup or transfer from another Mac): imovie 1025 dmg install
The only legal way to obtain the iMovie 10.2.5 DMG is: macOS Gatekeeper blocking the app (common if the
Drag the iMovie icon directly into your Applications folder. imovie 1025 dmg install
A: Only on macOS Mojave with an official eGPU enclosure. Performance gains are minimal.
*If you are running macOS Catalina or Mojave, you will need an older version of iMovie (such as 10.1.14). Attempting to install 10.2.5 on an incompatible OS will usually result in an error message.